Steel City 59361-1/2 Handy/Utility Outlet Box Extension Ring, Drawn Construction, 4-Inch Length by 2-1/8-Inch Width by 1-7/8-Inch Depth, Galvanized Steel Galvanized 13 cubic-Inch capacity Drawn construction (3) 1/2 inch each side, (1) 1/2 inch each end knockouts