Aqua Lung 5mm Superzip Elite Boot Ergonomically shaped for left and right feet. 5mm regular neoprene with elastic bound top for maximum resistance to wear and tear #10 YKK zipper with locking hook and loop tab to keep the zipper from sliding while in use 5mm Supratex neoprene zipper panel to prevent the zipper from tearing out under stress 2mm thick rubber toe and heel caps protect your boots when used heavily