These tendon boots have a durable outer layer which protects against direct impacts as well as deflecting indirect impacts. This outer layer combined with an inner shock-absorbing foam layer work in harmony to offer the utmost protection. The moisture-wicking lining and open front design helps keep the legs cool. This anatomically shaped boot offers protection where you need it most without the bulk that many other boots have. Kept secure with two "Quick Grip" straps.One size fits most average horses