Boot Sizing: Measure around leg halfway between the knee and fetlock Small = under 7" Medium = 7" to 8" Large = 8" to 9" Extra Large = 9" to 10" The H-20 Sports Support Boot fills the gap between the traditional bulky sports medicine boots that provide support and splint boots that provide protection but no support. The Sport Support Boot is a low profile support that provides protection with support. The support is ideally suited to the show ring, round pen, and race track. Constructed of orthopedic grade neoprene in the patented PRO design. The equal length fetlock support strap allows the user to adjust the angle and amount of support to fit the horse. Completely machine washable. Packaged in clear resealable clamshell boxes. Available in small, medium, large and extra large in a variety of colors. Refer to size and color charts.