The Remington 1100/11-87 12 Gauge Gas System Kit will help keep your firearm working its best with genuine factory replacement parts from Remington. It comes with a nickel-plated piston/piston seal and three teflon coated barrel seals. It fits all Model 1100 and Model 11-87 12 GA Shotguns and the kit will also work on the 16 GA models.