For over 46 years it has been about protection. Protection from debris, roost, rocks, and branches. O'Neal offers the extra layer of protection a fabric jersey can not provide. When it comes to safety and function, O'Neal's full line of protection provides sizes, features, and function for every type of rider on all types of terrain. Lightweight flexible and comfortable foam chassis design. Injection-molded plastic shoulder pads. TPR chest and back protection for supreme protection. Adjustable straps for the perfect fit. Sizing: X-Small / Small: Fits ages 2 - 5 years (approximately 35 - 40 inches tall, 28 - 40 pounds). Medium / Large: Fits ages 5 - 7 years (approximately 40 - 50 inches tall, 38 - 55 pounds).