The reins attach to the bit and connect the horse to the rider, who should hold them lightly and with respect for the horse's mouth. There are many kinds of reins, generally made of flat or braided leather, though reins can be rubber, nylon, or braided mohair rope.
In English riding, the reins are connected in a single loop from one side of the bit to the other, usually buckled in the middle, and are almost always leather.
In Western riding, the reins (or roping reins) might be connected, as in English riding, but are more commonly open or split. Open reins are 6 to 8 feet long, made of a variety of materials, and not connected at the ends.
Closed reins, also called California reins, have three parts. The two side reins are connected by a long quirt or romal, which hangs down by the horse's shoulder.