The Centaur Double Thick Bottom Pull On Rubber Bell Boot is a basic ribbed bell boot that pulls over the hoof to provide protection against interference and shoe loss for horses that overreach. The extra thick bottom edge adds extra durability, while the top of the boot is still nice and stretchy (especially the Gum version). Made of 100% pure rubber, with no fillers. Black, White, Gum. Medium, Large, X-Large, XX-Large.