Excuse my ignorance people but what is this? and what is it used for?


honest question! i really would like to know ;)
(love the boots in the first photo btw…)
i see many of you have been answering on the running martingale, well its not that what i mean! lol i want to know what the piece of leather under the horse’s chin and attached to the back of the noseband is. Thank you :)