ISTs 3mm tall cut boots with a super-thick 10mm (0.4 inch) felt sole are great for beach diving, traction on jagged, slippery coastal reefsor just ensuring a sure-grip for clamoring up a slippery boat ladder. Hard, thick sole is ideal for a wide range of surfaces and provides maximum protection. Toe and heel caps provide even more foot protection; boot has super heavy-duty no. 10 YKK zip these rugged boots are built for your feet to take it all. This is a highly unusual boot with its unique combination of a thinner 3mm body, and super thick 10mm sole.