No fitting or sizing needed for these pre-molded flanged silicone earplugs designed for ultra soft, ultra comfortable, waterproof protection. Mack's unique triple flange design allows for a more customized fit, which increases its sealing ability and improves wearer comfort. Doctor recommended to seal out water, Mack's AquaBlock Earplugs help prevent swimmer's ear and surfer's ear. Shatterproof carrying case included.