The most nice piece of neoprene you will ever wear. Cut and Built for Girl this HydroSkin shirt will keep you warm on those warm days when the H2O is cold and makes a great base layer for cold weather.0.5-mm Terraprene neoprene layer keeps you insulated and stretches easily. ThermalPlush inner lining increases insulation, repels moisture and dries quickly.4-way stretch PowerSpan outer layer allows easy, unrestricted mobility. Lycra underarms eliminate binding, adding to this top's superior function either as a single outer layer or as a base layer. Titanium laminate adhesive aids in body heat retention. DWR coating forces H2O to "bead" and roll off the material.