Backer boards (PAIR) for the sill plate on any 1971-73 Mercury Cougar or Ford Mustang. Also called a shield, it bridges the gap over the channel for the wiring harness. It is adjacent to the sill plate, and keeps the carpet from dropping into the exposed channel. This is a new part, and made from durable non paper material. See our related items for used. Original Ford part number D1ZZ-6513218-A. Two required per car, sold as a pair.