- Part of the US military Extreme Cold Weather Clothing System (ECWCS) and made using thick and warm polar fleece, this jacket will quickly become your favorite either as a standalone jacket or as a liner under a shell (like our Field Smocks). Features include reinforced shoulders and back of arms, two large zippered pockets outside and two open pockets inside, high collar, underarm zippers, elastic adjustable drawstring and adjustable cuffs. Black.