U.S. Divers 3 mm Purge Low-Cut Snorkeling and Diving Boot Low-cut snorkeling and diving boot for protecting feet while wearing fins 3 mm neoprene upper and 5 mm inner sole are sturdy and comfortable Vulcanized rubber sole with puncture-resistant layer and low-profile grip pads Water purge at heel for expelling excess water; rubber toe and heel cap Available in adult sizes 5 to 13; 2-year limited warranty