Steel City 15.8 cu in Octagon Galvanized Steel Box Extension Ring Silver

Steel City 55151 1/2 3/4 Octagon 4" Box Extension Ring is used when you need to add extra wire capacity to an octagon box. Mounts directly on top of the octagon box. Extender has 4 KO"s: one 1/2" conduit knockout on two side. and one 3/4" conduit knockout on 2 sides.