Adult Neoprene Skull Cap 3mm Swim Caps For Surfing Scuba Diving Kayaking Rafting neoprene Imported Unisex swimming cap with a comfortable chin strap and double seams. Best for cool/chilled water activities . Skull cap is made of water resistant neoprene which stays soft and flexible at any temperature. Swim caps protect ears from water penetration, help to prevent swimmer's / surfer's ear, hypothermia . Skull caps are suitable for swimming, surfing, scuba diving, snorkeling, kayaking, paddling, rafting. The swim hat is warm yet thin and lightweight enough (3 mm / 3.6 Oz) to fit under whitewater helmets.