4 oz./yd² (US), 6.7 oz./L yd (CA), 100% recycled polyester Coolcore® mesh; Moisture-wicking performance; UV 15-39 protection; Thermal regulating; Self-fabric collar with integrated collar stand and built-in collar stays; Recycled material made from plastic bottles; Coolcore® technology is chemical-free, mechanically engineered performance that doesn't wash out; ;