This innovative membrane stops water droplets and wind passing through the jacket while the fleece keeps you warm in water column tests this membrane produced a hydrostatic head reading exceeding 20 000 mm and will keep this performance even after multiple washes this garment is certified ptfepfc free ptfe and pfcs flourocarbons are the sort of teflon like nano particles which are applied to fabrics to make them waterproof however they are known to be harmful and can get into the water