Sandwiched between those layers is a 100 waterproof membrane made in britain by porelle 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 fluorocarbons are the sort of teflon like nano particles which are applied to fabric