What are terrets?

Some articles on terret, terrets:

... A terret is a metal loop on horse harness, guiding the reins and preventing them from becoming tangled or snagged on the harness ... The reins run from the hands of the driver, through the terrets, and then attach to the horse's bit to guide the horse ... Most harness has two pairs of terrets, one on the harness saddle, and one on the hames of the collar (or on the neck-strap of a breast collar) ...