Sleek, stylish design Interior adjusts to create snug fit on head Fits heads 48 - 54 centimeters in circumference Adjustable chin strap for secure fit Easy-to-use safety buckleThe Radio FlyerA(R) Helmet provides a cool way to be safe while riding. It has an interior adjuster that creates a safe, comfortable fit for heads sizes 48 - 54 centimeters. The helmet features a sleek, stylish look and an easy-to-use chin strap with safety buckle. For ages 2-5 years.