FOUND THIS INFO ON WIKIPEDIA
The ECWCS parka
The parka — which is a particularly popular component — is characterized by a cobra hood (which fits over a combat helmet) with woven nylon drawstring adjustable pulls and an attachment piece that allows fastening of a fur ruff (early models of the parka lacked this attachment piece). There is a two-way, full-front slide fastener to provide full-face protection, leaving only the eyes uncovered. The parka has Raglan shoulders/sleeves, a non-freezing, double-pull zipper with storm flap and seven snap closure, a flap-covered pocket on the left sleeve with hook and loop (Velcro) closure, adjustable hook and loop wrist cuffs, armpit ventilation zippers and double reinforced elbows. A badge/insignia tab with snap is located on the storm flap. There is an interior back ventilation opening, two slash (handwarmer) cargo pockets on the lower front (with extra large flaps and double hook and loop single snap closure on each) and an inside draft skirt (windskirt) with elastic drawcords and barrel-locks at the waist (without pulls). There are also two concealed map pockets at the front zipper with hook and loop closures that can be opened without unzipping the parka.
The second generation (2G) ECWCS includes two different layers made with Polartec fabrics: the Polartec Classic 300 shirt and the Polartec Classic 200 overalls. When used in combination with other layers in the ECWCS system, the system provides protection between +40 °F and −40 °F (+4 °C and −40 °C). 2G ECWCS is currently being worn by US Special Forces, US Army and US Air Force soldiers stationed in extreme environments from Norway and Bosnia to Afghanistan.
The third generation 3G or GEN III Extended Climate Warfighter Clothing System is a radical re-design of the system. It features seven new layers of insulation including three Polartec fabrics: two layers of Polartec Power Dry and a layer of Polartec Thermal Pro High Loft. The 12 components of the GEN III ECWCS include a lightweight undershirt and drawers, midweight shirt and drawers, fleece cold weather jacket, wind cold weather jacket, soft shell jacket and trousers, extreme cold/wet weather jacket and trousers, extreme cold weather parka and trousers. Initial fielding of the system began in August 2007 to the 73rd Cavalry Regiment in Afghanistan.