Conduit wiring system. Welded, with conduit knockouts. Four 3/4 in and four 1 in conduit knockouts (sides). One 1/2 in conduit knockout and three TKOs (bottom). 4-11/16 in square x 2-1/8 in D. 42 cu-in. Installed in ceilings or walls for lighting fixtures or receptacles. UPC code. UL listed.
