Bit guard

A bit guard (cheek guard in Australia) is a specialty piece of horse tack: a washer, usually made of flexible rubber, that is sometimes used in pairs on a bit.

Reasons for using a bit guard include:

A pair of bit guards is placed on a bit by stretching them to pass over one bit ring. Then the bit is attached to a bridle. The bridle is then put on a horse so that the bit guards lie outside of the horse's mouth. Bit guards are used with loose ring snaffle bits, gag bits, and pelham bits. Bit guards are used more often in jumping events, such as eventing and show jumping, and in polo. They are not permitted in competitive dressage, and are not used in horse show hunt seat competition.