Enclosed Cargo Trailer Rear Door Bumper. Also Used on Dump Trailers. Boat Trailer End Cap RollerYATES durable black rubber flat roller end cap 1/2" shaft, 2-1/2" end width, 2-1/2" height .End caps provide added protection for boat hulls by covering exspode metal ends of the roller brackets.Used on side guides and many flat bottom applications .Sold as each