IST Titanium Sole with Toe/Heel Caps & Spandex Lined Boots for Scuba Diving/ Snorkeling Diver 3mm/5mm/7mm Titanium and spandex lined neoprene boots with Vulcanized rubber sole All seams blind-stitched and double-glued to keep water out, increase seam strength Toe and heel caps for additional support and protection Built-in fin strap cleat helps keep fin straps securely in place #10 ultra-durable YKK zip with inner gusset to prevent seepage