Trek Tyro Youth Bike Helmet 1643-5306955 The Trek Tyro is a dedicated youth helmet packed with the same performance and comfort found in adult helmets.A Fidlock magnetic buckle lets kids secure the chin strap easily, and an simple-to-adjust dial fits a wide range of head sizes. Plush pads make the helmet comfortable for a full day on the bike. Features Dialed fit system provides a snug and comfortable fit Soft, comfortable, moisture-wicking, and washable helmet pads Adjustable helmet straps provide a clean look and easy fit management Crash Replacement Guarantee provides a free helmet replacement if involved in a crash within the first year of ownership Helmet meets ASTM standards-their tests use a smaller mass headform more realistic to younger riders In-molded EPS shell with additional rear coverage for protection and durability Complies with U.S. CPSC safety standards for bicycle helmets for persons age 1 and over Fidlock magnetic buckle fastens effortlessly for a quick, kid-friendly fit Trek Tyro Youth Bike Helmet