Our only fully waterproof thermometer. ChillChek's housing is fully enclosed and IPX8 waterproof. Includes a reflective, break-away lanyard for high visibility and a brass splitring, so you can quickly clip it on your zipper, backpack, keychain, or other outdoor or marine gear. The perfect thermometer for swimming, diving, fishing, or any other water sports. Depth-pressure tested up to 150 feet (45 meters). Great addition for any future diving, snorkeling, or boating trip!