ringbit

ringbit

(ˈrɪŋˌbɪt)
n
(in horse racing) a piece of equipment worn by a horse which has a ring at the end that is passed through the horse's mouth
References in periodicals archive ?
I couldn't see us beating the favourite, but my horse is a decent yardstick on his day and we put a ringbit on him to stop him hanging.
Sheikh Mohammed's colt had been beaten less than a length by Voltigeur winner Fantastic Light last August, and, with the help of a ringbit, he seems to have harnessed his enthusiasm into a potent winning force.