This is the DUI XM450 Cold Water Drysuit Fleece Lined Socks for Dry Suit Scuba Diving Features: Made with Thinsulate(TM) Ultra Insulation 400 gm/gm with provides the greatest amount of warmth per unit of thickness available -black Polartec PowerStretch Pro560 gm/m2 at ankles for warmth and comfort Wind-and-spray resistant outer shell with high tenacity technical ripstop Cordura bottom for durability Thinsulate drysuit socks for your drysuit Fleece lining for warmth and comfort Antimicrobial liner Sizes XS, S, M, L, XL, XXL Fast becoming a favorite accessory among avid dry suit divers!