Oh - huh- I was wondering if the metal loop that hang down works like a psuedo curb strap, but having no leverage that didn't make sense. I suppose maybe it's used for leads? Like thoroughbreds have the loop IDK what it's called.
Basically, you can put the reins on one of two spots, in front of the chin cage, or behind it. It is used on racers that are very strong and like to just barge ahead.
It's to keep the horse from opening its mouth too wide. When you lead a race horse, you put the pony strap right on the bit for the most control. It also keeps the bit from flipping in the horse's mouth.
Ohhhhh very interesting! Thanks! I'll tell all the others who were curious. Why wouldn't they just use a curb strap or a nose band so they can't open their mouth too wide? I'm just curious xD