Reins attach to the bit on the bridle. The elasticated support reins are connected to the reins via a buckle, there are multiple buckle holes along the rein to allow for size adjustment. The support reins clip to the D rings at the front of the saddle on each side.When the rider has contact on the reins the elasticated support rein will lie slack. If the horse tries to pull the reins out of the riders hands, the pull is taken up in the elasticated support rein and blocked at the saddle. The support rein is acting like a second pair of hands, preventing loss of control. Balance support reins promote confidence within the rider and promote a good balance.Approx Guide Small Pony - upto 11.2hhPony - 11.0hh to 12.2hhPony XL - 12.2hh to 14.2hhLarger build ponies may need to take a bigger size.