I have found several different types of boots to choose from.
Old Mac 1 and 2
EasyBoot - Glove, Epic, and etc
Cavallo Simple Boots
Tough-1 Rubber Hoof Guard
I am wanting to use them for trail riding for the front feet only for a horse that has been lame and showed some signs of being laminic, slight case of founder, or in other words.... exrays showed a slight turn down in the toe bone.