Military Thermals – Professional Grade Thermals 100% Made in the USA!

Military Thermals polypropylene thermal underwear is 100% made of high quality polypropylene fabric made right here in the United States. From the beginning of our supply chain through our finished product, all Military Thermals brand products are made of US materials with US labor. 100% made with pride in the USA!

Military Thermals long underwear is part of the Generation I Extended Cold Weather Clothing System (ECWCS) established by the U.S. Military. There is simply nothing better and more economical. Don’t be fooled by high priced, store bought brand names that cost three, four times as much, Military Thermals are the first choice of military personnel around the world and for good reason. Military Thermals retain more of your body heat than any other fabric. Polypropylene thermals are the best extreme cold weather base layer of clothing made. High quality Military Thermals polypropylene are comfortable and affordable thermal underwear that was specifically designed to keep you warm and dry from cold to extreme cold conditions. Stay warm this season while enjoying all your outdoor activities – working, hunting, hiking, camping or your favorite tailgate party – all are more enjoyable when you’re warm. The secret is low thermal conductivity, in fact polypropylene has the lowest thermal conductivity of any apparel fabric available. Don’t pay more for less – Compare Military Thermals to other expensive store brands and you’ll discover a world of difference in price and comfort.


How polypropylene keeps you warm and dry.

History of Polypropylene in thermal underwear

Polypropylene is a thermoplastic polymer used in a variety of applications, including as a base layer in the first generation of the ECWCS (Extended Cold Weather Clothing System). The ECWCS was developed by the United States Army as a protective clothing system. The system used a triple layering system to created an insulated platform to maintain a soldier’s mobility and survivability in extreme environments. The entire system consisted of 22 total items from base layer to exterior parka including gloves, socks, boots, etc.

The original Extended Cold Weather Clothing System (ECWCS) was upgraded to the second generation to improve limitations of the parka fabric which did not breathe well and as such created limitations for the system as a whole in the field. The second generation, Gen 2 ECWCS included two different layers made with Polartec® fabrics: the Polartec Classic 300 shirt and the Polartec Classic 200 overalls. The parka was improved with vents to help deal with the condensation problems created by the waterproof parka material.

Third Generation, Gen 3, Gen III, ECWCS was a substantial change from the prior two generations, featuring 7 new layers of insulation. Three of these new layers are Polartec fabrics; two layers of Polartec Power Dry® and a layer of Polartec Thermal Pro High Loft®. With these changes brought additional expense to the system as a whole, specifically to the lighter weight, higher cost Polartec base layers.

These new Gen 3 Polartec base layers do preform their function better within the confines of the system for which they were designed to operate. Do they perform equally as well outside of the ECWCS? We think they do not. The original Gen 1 polypropylene thermal underwear is in our opinion the best performing and most comfortable product to be worn for everyday use as thermal underwear outside the confines of a military survival system. Many of our armed service men and women still prefer Gen 1 polypropylene and many military procurement specialist purchase our product to serve this demand.

In recent years polypropylene fabric has been exceedingly difficult to find; impossible if you were searching for a made in the USA product. The immediate solution was a Chinese produced alternative. Frankly, it’s not a bad option and one that even we were forced to embrace while searching for an alternative solution. Many brands you may be familiar with like the Bass Pro RedHead E.C.W.C.S. claim to be “military fleece thermal” and they are not. These products and others like them are produced with polyester, not genuine polypropylene. Polyester is stiff and not nearly as soft and comfortable as polypropylene. You really can feel the difference.

Military Thermals is proud to produce our own brand of genuine US Mil-Spec Gen 1 thermal underwear at our offices in Fort Wayne, IN. Military Thermals brand polypropylene thermal underwear are produced with 100% materials made in the USA and with 100% US labor. Military Thermals are 100% made with pride in the USA!