Light Weight Base Layers Page 1, 2
This section features 'Next to skin' garments

As a sizing reference: I'm 5'7", 155 lbs (yeah, I'm a little guy), medium build (BDU top medium/regular, BDU pant medium/short), waist 32", chest 43". Keep this in mind when you read my comments with respect to sizing, so you have an idea of how the garments featured below will fit on you. ALL garments in these pages are size Medium, unless stated otherwise.


Military Clothing Systems

Over the past decade, we've finally been seeing the military take notice and adopt some of the advanced technology/high performance fabrics and clothing that civilian mountaineers and backpackers have been using for quite a while. Lighter, more compressible, breathable, quick drying and wicking fabrics now clothe the soldier, doing their part to make a tough job a bit more efficient and a bit less uncomfortable. Clothing the soldier presents a unique challenge as temperatures in certain regions may range greatly over a 24 hour period, or missions might start off at low altitudes and end up much higher. Soldiers most often have to be self-sufficient, carrying everything in their rucks and on their person, so light weight and clothing versatility rank high in importance. Unlike most sporting events, the soldier might have to wear the same clothing for days or weeks on end, and subject them to abuse that civilian use won't.
There are quite a few different clothing development programs out there, and it can be confusing. Since I have no personal knowledge on the subject, I've summarized some of the info from Polartec® literature and other sources like the U.S. Army programs website. I've given credit to the sources of information where possible, and if there's any violation of website policies, webmasters please let me know. Polartec® manufactures much of this high-performance material, and their website is a wealth of information, so please visit it for details. This list is by no means all-inclusive - there are a LOT more programs out there, but I've chosen those that are relevant for this website.

  • ECWS - Extended Cold Weather Clothing System. Cold-wet and Cold dry systems, including the Gore-tex suit and insulating layers
  • SPEAR - Special Operations Forces Personal Equipment Advanced Requirements - A performance layering system developed by SOCOM.
  • MCPS - Multi-Climate Protection System - NOMEX flame resistant clothing for U.S. Marine and Navy aviators and aircrew.
  • SOF-PCU - Special Operations Forces Protective Combat Uniform - Layering garment system with 7 Levels developed by USSOCOM. The different levels are defined as follows (from this website). Also note that the actual products offered may vary slightly from these descriptions:

    Level 1
    Worn next-to-skin, a durable, silkweight Polartec Power Dry fabric worn next to the skin wicks away moisture and dries fast. It consists of a crew neck T-shirt and boxer shorts, or is available in long-sleeve top with invisible zipper and pants, built for comfort and minimal weight.
    Level 2
    A long-sleeve shirt and pants made from Polartec Power Dry fabric are worn next to the skin for extra warmth in extreme conditions, but still wicks away moisture quickly from skin and dries fast. An inserted side panel of Polartec X-Static fabric enhances fit and flexibility. The top has a front 15-inch zip for extra venting and a soft lining around the collar. Comfort features include an articulated side seam on the pants to minimize chafe on the kneecap.
    Level 3
    An insulative mid-layer jacket made from Polartec Thermal Pro fabric is water-repellent yet breathable. It is worn as an outer jacket in mild temperatures or as a heavy insulative layer in extreme cold. Seamless shoulders minimize chafe, which are then lined for extra warmth and padding for heavy pack straps.
    Level 4
    The soft windshirt is made from an encapsulated microfiber that repels water but also breathes for a variety of conditions. It's designed to pair with a next-to-skin layer for intense activity in cooler temperatures or with the Level 5 soft shell as a mid-layer. It stuffs into its own pocket for easy packing.
    Level 5
    The key to the entire system, this soft shell fabric jacket and pants are made with fibers encapsulated with silicone that are highly stretchable, windproof, water repellant and breathable. They are paired with Level 1 or 2 next-to-skin layers, ready for any cold weather aerobic activity.
    Level 6
    A lightweight waterproof and coated nylon hard shell is slightly oversized to fit easily and quickly over gear. The jacket features water-resistant zippers and armpit zips for maximum ventilation, pocket openings to quickly access inside layers and a hood that incorporates a stiff brim. The pants borrow the same design from Level 5 but provide waterproof protection.
    Level 7
    For extreme conditions, this lightweight, loft-insulated level in a jacket, vest and pants has the feel of down but retains its warmth when wet. Silicone-encapsulated fabric sheds water and is paired with Primaloft insulation for maximum warmth while the liner pulls away moisture.
    Level 8
    SOF-CCU (Close Combat Uniform) - Basically a RAID-type BDU.

Typically, there can be several different manufacturers/contractors making the same garments. Sometimes different manufacturers make different levels in the same program, and I hope to feature more of them here. I'm also learning that the item of the same name might vary by manufacturer with differences in materials and features. I was surprised to find this out, and expected the garments to be more standardized.


2/13/05 - Insport is a well known manufacturer of well designed and high quality athletic clothing which has been around for quite a while; I remember buying Insport cycling apparel when I was bike racing at the collegiate level, more than 15 years ago. Relatively recently, Insport landed a contract to produce clothing for the U.S. Navy, and shown here are a few items from their military line (which is available for purchase to civilians).

NS21 PCU Level 1 Lightweight Pant (below) - The Level 1 lightweight pant is constructed of Polartec® Power Dry® fabric with X-STATIC® in coyote brown. Intended to be worn next-to-skin as a base layer, the fabric is a wicking material, designed to keep your skin dry when you sweat. It's a bi-component knit that uses different yarns on either side of the fabric. Look at the photos above and you can see the inner surface which is optimized to move moisture away from the skin, and the outer surface, for fast drying. X-STATIC® inhibits the growth of odor-causing bacteria in the fabric, and incorporates pure silver-bonded fiber that is permanantly knit into the fabric construction and will last as long as the fabric does.
The pant has a comfort fit - not too loose and not skin tight like some undergarments. Personally, I prefer the looser fit to one that is skin tight. I like the feel of the Power Dry fabric, which feels more like a natural fiber than a synthetic. I dislike the synthetic feel of some popular tight fitting undergarments. The pant has an elastic waist band (a bit tight around my 32" waist, but it could loosen with use) and front fly opening. It's extremely lightweight and comfortable to move around in. I went running in these in low-60° weather, and they kept my legs warm enough until I warmed up but didn't feel overheated as I was running. After cooling down and I was pouring sweat, they dried fast whereas my cotton briefs were soaked with perspiration for a while.

Level 2 Tee and Level 1 Pant

Front details of Pant



3/2/05 - SEKRI stands for South Eastern Kentucky Rehabilitation Industries and is a "non-profit organization whose primary purpose is to provide qualified personnel, facilities and related services for persons with disabilities, enabling them to obtain and to be successful in maintaining competitive employment". SEKRI manufactures Levels 1 (bottom wicking layer), 2 (added warmth) and 7 (water/wind resistant high loft insulated) garments of the SOF-PCU multi-layered cold weather system. All items are can be ordered directly from SEKRI online here.

PCU Level 1 T-shirt and Boxer- The Level 1 Silkweight T-shirt and boxer are constructed of smooth Polartec® Power Dry® fabric. Designed to keep your skin dry when you perspire, the stretch material has a smooth texture that feels very soft next to the skin. Depending on the light, the material (and most of these other PCU materials) can look "bronzine/gray-green" (as described on the SEKRI website) under fluorescent lights to a coyote-ish brown under natural and incandescent lighting. The medium size T-shirt was a perfect fit for me and cut very comfortably - no binding or restrictions; neither too tight nor loose. It's cut longer in the back than in the front, which seems to be common feature amongst the PCU garments.
The silkweight Boxer short is made of the same wicking material. I've worn the T-shirt to the gym and went running in it, and the difference between it and a cotton T-shirt is very noticeable once I start to sweat. It doesn't feel 'heavy' or clammy, and dries much, much faster. When doing laundry, I took some of the Power Dry fabric garments out of the washer along with similar cotton items, and let them dry naturally instead of throwing them in the dryer. The Power Dry garments were dry long before the cottom ones, which stayed damp for a long time.

Level 1 T-shirt front

Level 1 T-shirt rear

Level 1 Boxer front

Level 1 Boxer rear

PCU Level 1 Long Sleeve Shirt and Pant- Also meant to be worn next-to-skin, the Level 1 Long Sleeve Shirt and Pant are made of the same Polartec® Power Dry® fabric with X-STATIC® I've already covered in the Insport review above. Rather than the silky fabric of the T-shrt and Boxer, it has minute holes in the outside surface that aids in evaporation of moisture. A 12" zip in the front closes the 2.5" high collar. Also cut longer in the back, it'll stay tucked in.
The Level 1 Pant varies from the Insport product by having a wider middle gusset, and slightly looser plush waistband. Overall fit on me is about the same. It has a front fly opening. I can't stress how comfy these items are to wear. They're a perfect balance for when it's too cool for shorts and a short-sleeved t-shirt, but not cold enough for sweats.

Level 1 Long-sleeved shirt and Pant

Pant waist band

3/23/05 - Wore the Level 1 long sleeved shirt and Level 2 Long sleeve shirt on a short hike. Temperature went from about 62° to 57°. Pretty strong, cool breeze. I was comfortable-warm with both on, and on the way back, when I started working up a sweat, I had to remove the Level 2 as it got too warm. The Level 1 kept me comfortable on the move despite the breeze and dropping temp.

APCU Level 1 Baselayer Top

10/5/08 - Adventure Tech, which is a custom design and R&D house for Military and Outdoors companies and brand names teamed up with Propper on the Adventure Tech Series; the Adventure Tech Series by Propper is an exclusive project for Propper. An interesting development is that Blackhawk Products Group recently acquired Adventure Tech giving them access to even more manufacturing and prototyping resources.

Adventure Tech's APCU (Advanced Protective Combat Uniform) mirrors the PCU (Protective Combat Uniform) system with the seven garment layers. The Adventure Tech APCU Level I - SS (Short-Sleeved) Lightweight Baselayer Top (available from USCAV) is a stretchy, Level I base layer shirt with breathable panels and X-Static silver fiber.

Material - The APCU Level 1 Light Weight shirt is made of a synthetic stretch fabric with 'activated Carbon-Tech with 5% X-Static silver lining'. The activated carbon embedded within the Carbon baselayer fiber is supposed to improve the perspiration process by pulling moisture away from the skin to bring it to the fabric surface for evaporation. The X-Static silver is anti-odour, anti-static and anti-microbial. The APCU L1 shirt also provides Ultraviolet Protection up to UPF 50+ and is designed to be the worn next-to-skin as the first layer in the system.

Rear view

under arm mesh panel

General Description - The APCU L1 shirt comes in Coyote, Alpha Green (shown here - it's actually grey) and Black. There are seamless, super-breathable panels woven into the center of the back and under the arms, extending down the sides. This is part of the 'body mapping' technology along with no seams on top of the shoulders to reduce hot spots. All seams are flat for comfort.

Observations - When I first got the APCU L1 shirt, the material didn't feel as soft as I had anticipated it would. It's not a silky soft fabric like the Zensah shirts, but textured a bit more like the Insport base layers I have. The plus side is that it's not as snaggy on hook velcro as the Zensah and feels more durable.
When I first put it on, it actually felt a bit scratchy - a bit like Merino wool. 'Merino wool scratchy? I'ts not scratchy..' you might say. As noted in other areas of this site, I have skin that is very sensitive to itch or scratchiness, which might not be shared by others. In fact, my friend Hawkeye who recommended I try this shirt (it has become his favourite hot-weather top) feels that it's the most comfortable he's tried. The breathable mesh panels are very soft - I had no probs with those. Another thing I noticed was that mini-bartacks are used at to finish off the flat seams at the junction of the mesh panel and the outer sleeve fabric; under the arms at the end of the sleeve cuffs. I also found those a bit irritating on the inside skin of my upper arm. I would have preferred if the mesh panels under the arms were wider, with the seams more to the outside instead of under the armpits. I decided to give the shirt a few washings to see what would happen, and sure enough, it got a bit softer and so did the mini-bartacks. It turned out to be pretty comfortable after all - it just needed some breaking in. I still think the seams could be relocated though.

The APCU L1 shirt is pretty long. Well, I have a short torso, actually. Even so, it extends almost all the way down to my hands - more like a 'medium long' fit than a 'medium'. I think the bottom hem can be shortened by about 2-3" with still plenty of length left to tuck it in. It doesn't need to extend to my crotch or below my buttocks. It stretches - it's not going to become untucked when you bend over. The fit on me is tight around the arms, more relaxed around the torso, and a bit loose at the collar. So, it's not really a compression shirt - only in the arms (and I don't have big arms). I'd rather it fit consistently over my whole body - either all tight or all relaxed. That's just all personal preference, though. The sleeves are also a bit longer than normal, which I like. If they're too short, they tend to ride up my arms and bunch up under the armpit. For me, the APCU shirt sleeves are the perfect length.

I used this shirt for running/jogging, which is when I sweat the most. The way synthetic 'wicking' shirts work is to get soaked with sweat (which means it's drawing sweat off your body), then evaporating that sweat as it dries. While synthetic shirts may not get soaked as quickly as natural fibers (it takes a while for the capillary action to work), they dry much faster, and stay lighter and feeling drier while doing so. As far as performance, the APCU shirt did very well. I was sweating profusely and the APCU shirt was able to soak it up, and yet remain feeling relatively dry to the touch. To me, that means that sweat was being evaporated from it quickly. Once I stopped running, it got soaked with my sweat more, since I was no longer moving through the air, but still dried very quickly. If I was wearing a cotton T-shirt, I'd be soaked in my own sweat for a while.
I like those mesh panels, and can feel the difference when there's a breeze. I thought, "Why not make the whole shirt out of this mesh fabric?", but realized that it might suffer in durability and abrasion resistance. While the rest of the shirt is relatively snag resistant, the mesh panels will snag on hook velcro (which I found when putting it on under body armour), so keep that away from them.

In summary, the APCU shirt performs well and dries very quickly. While I would have preferred the APCU to fit more consistently overall, that's my personal preference and also dependant on body shape. It might fit someone else perfectly with a different physique. My issues with some scratchy bits (which got better after break-in) were not shared by Hawkeye, and this is probably because I'm particularly sensitive.


ARC'TERYX LEAF (Law Enforcement and Armed Forces) Products

Note that the product line is subject to change - some of the items below may be discontinued or changed from the time the review is written.

4/23/05 - Vancouver, BC, Canada-based Arc'Teryx is a well-known name in the outdoor world, producing the latest, high-end outdoor clothing, gear and accessories. Up till only a few years ago, military clothing technology has usually been a step behind what's been available on the civilian market. It makes sense that leading manufacturers of 'technical' outdoor clothing are entering the military market but it's more complicated than just producing civilian clothing in 'military' colours. The Arc'Teryx LEAF (Law Enforcement and Armed Forces) Purchase Program makes special versions of their product line available to military and LE professionals.
Side note: Arc'Teryx's logo is the fossil (actually, the Berlin Specimen found in 1877) of the Archaeopteryx, the prehistoric animal that looked like a bird, yet also had some of the features of a dinosaur/reptile. There's controversy over whether Archaeopteryx was the first bird, a reptile, or a transitional species, but in general, Archaeopteryx is viewed as a 'first of its kind' and a symbol of evolution. A good choice, symbolizing one of their mottos - 'Evolution in action'.

4/28/05 Blaze Zip Short Sleeve T-shirt - The Blaze Zip SS T-shirt is a very lightweight (5.1oz) T-shirt made out of 100% polyester Breezon™fabric, which has a structured knit for next-to-skin moisture management. The next-to-skin surface of the fabric has a tighter weave to wick and absorb moisture while the outer surface has a more open weave for faster evaporation. The colour shown here is 'Cinder', which is an extremely dark grey, as far as I can tell. Not quite black. It's available in crocodile as well.
An 8" zipper in the front with a nicely contrasting pull adds some control over ventilation and cooling. The pattern is different from conventional T-shirts - there are no seams on the top of the shoulders, and all seams that join the panels are flat-locked for comfort. High stitch count construction throughout. The collar is a very comfy, low profile design and the printed label in the inside back of the neck saves you having to cut one off. The Blaze is cut a bit shorter than the Emissary shown below, but still long enough to tuck in. It's a bit longer in the back, as well. The fit is athletic (which I am finding out is the norm for Arcteryx). Subdued logos are on the left sleeve and on the left hip (bird logo).

Front view


Rear view

Close up of fabric and sleeve logo

Is a front zipper really necessary on a 'simple' T-shirt? Not until you wish you had one. It provides that little extra bit of temperature management that makes a difference. I was running in the evening at the time when it's usually a bit chilly, until I warm up and start to sweat. I experimented zipping and unzipping the front while running, to see how much of a difference it would really make, and it was quite noticeable. Zipping it all the way up closes up the collar, and keeps the wind out. Zipping it all the way down ventilates the entire shirt by making it that much looser while running, allowing air to circulate as I move, and warm air to vent. The Blaze also dried pretty quickly, and didn't have that soaked, clammy feel of cotton. I like the overall fit and cut of the shirt - it's unrestrictive when working out and smart-looking as well. Very comfortable. It's shirts like this one that are prompting the slow change over from cotton to synthetics in my wardrobe.

8/20/05 - Did a 7 mile medium-strenuous round-trip hike from 6000' to 10,000' with conditions ranging from hot at the lower altitudes to windy and chilly at the summit (still snow in some places). Wore the Blaze Zip T with my Kifaru Tailgunner and later with my wife's camelbak Hawg and I was comfortable the whole time. I never felt clammy or damp even though I was sweating quite profusely on the way up - the front zip was a plus as I could ventilate when needed and zip it up when it got chilly.

Emissary Short Sleeve T-shirt - The Emissary SS T-shirt is a lightweight (6oz) summer shirt made out of superfine Merino wool. Why wool? Wool has a lot of superior qualities, some of them being durability, insulation for both hot and cold climates, absorbance (wicking), flame resistance (natural fibers are recommended if exposure to flame is a risk), and resilience, to name a few. I'll have to admit that I've never been a fan of wool, as I've experienced itching with most coarse fiber wool garments. It's only recently that I found out that no one is really 'allergic' to wool - the discomfort or prickly sensation is the skins reaction to fibers in the fabric that are greater than a certain diameter. I'm one of those people cursed with extra sensitive skin.
Superfine Merino wool, however, is supposed to have fiber diameters smaller than that which the skin will find irritating. Fresh out of the wrapping, the Emissary shirt definitely felt silkier than any of the wool garments I had worn in the past, but I did experience a slight irritation initally on my arm. I wore the shirt for about 24 hours straight (night and a day), and very soon into that period, my skin 'got used' to it and no longer felt as prickly. It improved after I laundered the T-shirt but still wasn't as 'smooth feeling' as a cotton or synthetic. I spoke to Dan Bergeron from Arc'Teryx's LEAF program and he was very surprised to hear that I had experienced any discomfort, as this was the first feedback of that kind. We agreed that it was probably due to my hyper-sensitive skin, to which I'm inclined to agree, and that I'm in the very small minority of people that even Merino wool can feel prickly to. (Hell, I've got an itch on my arm as I write this and I'm not even wearing a shirt - talk about the 'Princess and the Pea'.)

Front view

Rear view

Close up of logo

Enough about my skin - the Emissary shirt has flat-locked seams and a nice, athletic cut. Not as baggy as a regular shirt, and not too tight. It stretches with movement and is very comfortable, all around, when I got used to it. Plus the cool Arc'Teryx logo on the bottom. The main thing I noticed while wearing it was that it never felt too hot. I thought that it'd be warmer than a cotton tee, but it wasn't. Before lunch, everyday, I do a short workout in the temperature-controlled fitness room at work; enough to break a sweat. I definitely felt less warm and sticky with the Emissary shirt on than with my normal cotton tee. If you like Merino wool products, the Emissary might be a good choice for you.

S.O.D. Gear Skin 01 Shirt

10/11/10 - The Skin 01 Shirt from S.O.D. (Special Operation Department) is a stretch fabric 'compression' shirt designed as a snug-fitting light weight baselayer for comfort in all climates. S.O.D. is an Italian manufacturer of military clothing that collaborates with and produces clothing and equipment that is used by Italian and allied military units in a variety of theatres.

The stretch fabric portion of the Spectre DA Combat Shirt is essentially a portion of the Skin 01 Shirt.

Material - The fabric used for the Skin 01 shirt is a 4-way stretch-knitted fabric, reminding me a bit of the Zensah compression/stretch garments which were also made with fabric made in Italy. The S.O.D. fabric is a bit thicker with a more prominent knit pattern on the body, and very stretchy. There are actually two patterns in the fabric - the main tight pattern, and a looser one which forms a mesh, under the arms, for increased ventilation. The fabric is very soft, stretchy and comfortable. I asked about durability and was told that it's pretty decent, but not meant to be very abrasion resistant. After testing and production with some other materials, the end users preferred this fabric as it is very light and comfortable in theatre. There is also another version of the combat shirt with a FR fabric torso. Note that loop velcro can snag and make it pill, so be aware. The Skin 01 shirt is only available in the colour shown here, which is a lighter shade of S.O.D.'s 'HCS' (Hybrid Coyote Sage) colour. It's a dusty combination of sage and brown.

Collar details

Armpit mesh

Description - The Skin 01 is aptly named as it is supposed to fit like a second skin. Since it's very stretchy, it doesn't 'squeeze' tightly while maintaining a snug fit. The shirt has raglan sleeves, which extends in one piece fully to the collar, with a diagonal seam from the armpit to the front and rear of the neck. A more open mesh is woven into the fabric at the juncture of the sleeve and the torso, and extends on the inside of the arm midway down the fore arm for added ventilation. The collar is a smooth double layer for durability (so you don't end up with a floppy, wavy collar), and the wrist cuffs and bottom waist cuff are ribbed. The Skin 01 shirt is designed as underwear/baselayer, and not intended to be subjected to abrasive environments. Note that this, and most stretchy nylon garments will snag and pill on hook velcro.

Observations/Notes - What I've found over the years of using 'compression'/snug fitting shirts is that they wick sweat away from the skin more efficiently than a loose fitting garment. By having maximum surface area contact with the skin, they keep the skin drier as wicking transports moisture away from the skin much faster than evaporation. Snug fitting baselayers are also more comfortable when worn under other garments as there is less bulk, bunching, folding or binding from excess material. For strenuous activities in both hot or cold weather, I find a snug-fitting garment keeps me more comfortable as it can prevent chafing from skin-skin contact/rubbing, especially under the arms, and keeps the sweat away from the skin. The Skin 01 is one such garment, and performed very well under chilly to hot conditions for me. I used it for jogging in the evenings before the weather turned warm. It dries faster than a cotton t-shirt.

As a base layer, it's snug and doesn't add any bulk. It fit me very well and I didn't find any area to be too tight nor loose. I also found that it works well for sleeping in a sleeping bag as it stays put and doesn't ride up. As a stand-alone shirt in hotter weather (it's also available in a short-sleeved version), it wicks perspiration away and keeps the body drier and more comfortable than a loose-fitting shirt.




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