The Runoff is constructed from water-proof, breathable, stretchable soft shell fabric, which will be the industry standard in a few years. Usually that would seem enough to get you to bite. However, in classic Willy J form, they decided to over do it, so they added water proof zippers and wind stopper fleece liner and neoprene cuffs. The ultimate in performance disguised as comfort. It is fully taped and lined with micro fleece for absolute comfort and warmth. All zippers are watertight as well as internal neoprene wrist cuffs, the best defense available against that liquid we like to call water.