The adjustable and high elasticity design fits most kids to medium-sized adult heads. Aazon.co : Swiing Headband for Kids - 2 Pairs Waterproof Ear Plugs & Adjustable Swi Ear Aazon.co : Swiing Headband for Kids - 2 Pairs Waterproof Ear Plugs & Adjustable Swi Ear... MULTI-USE for Diverse Water Sports: these swim headbands can be great for swimming, surfing, canoeing, kayaking, bathing, water skiing and diving, bringing you a pleasant use experience. Swimming Headband for Kids Adults Adjustable Doctor Recommended Waterproof Swim Ear Band Protection to Keep Water Out and Hold Ear Plugs in-Water for Surfing,Diving,Pool,Showering,and Beach Best Waterproof Headbands for Swiing n addition to helping secure earplugs in place,Headband helps keep ears warm during cold water and winter activities and even help prevent hair from covering the face. Water Ear Plugs Adult 3 Pieces Swimming Headband Waterproof Swim Ear Band Elastic Ear Protection Band For Swimmers Kids Adult Block Water Secure Earplugs Water Protection Bath Shower Pool Beach (Vivid Style Swimming Ear Plugs Adjustable and Flexible:our Swimming Headband is available in two sizes to choose; The large size is (23., 23inch) fits adults aged 16 and above with head circumferences of 23-26 inches; The middle size is (21., 65inch) fits average woman or older child with head circumferences of 21-24., 5 inches; Before ordering, please measure your head circumference to avoid size issues and the hassle of returns; It's better to use a soft tape measure, a piece of string and a standard tape measure can also work.