IST Low Cut 3mm Neoprene Fin Socks/Slip On Booties for Swimming, Scuba Diving & Snorkeling LOW-CUT  Sleek, minimalist style includes an elastic ankle band for a snug fit. DURABLE CONSTRUCTION  Seams are double-glued & blind-stitched to reduce water seepage. CONSERVES BODY HEAT  3mm Nylon II neoprene insulates the foot to maintain warmth. EASY LAYERING  Wear alone or slip on under snorkeling fins for extra comfort. PERFECT FIT  Available in youth & adult sizes.