Men's Cold Weather Fleece-Lined ZIP UP Thermal Military ECWCS Shirts Extreme Winter Base Layer Undershirt with ArmyUniverse Pin - These base layer thermals are made from polyester and are exact like the polyproylene thermal undershirt you know and love. The Zip Up style offers extra protection for your neck and shoudlers like a thermal turtleneck would, but can also be opened to be used a V Neck type thermal. These cold weather thermals offer the same exact quality and warmth. You will love them and the comfortable mens thermals that we offer are going to be your favorite thermals. They are cut for men but can be worn by women as well. The fleece lined material, will always feel smooth and comfortable against your skin and the poly layer will repel moisture and offers breathability to keep you dry. Every thermal comes with an official Army Universe pin. We offer 4 colors and one is approved to be used by the US Army as it is AR 670-1 complaint.