Abstract: The fitting is mountable on a cellular steel floor or deck prior to pouring of the concrete of a completed floor and comprises a separable flat base plate, a box-like housing, and a cover plate. Two self-grommeted openings in the base plate are axially aligned with respective openings of substantially equal size leading to adjacent cells of the deck, and a tab on the base plate at one of the grommeted openings interlocks with the deck to hold the base plate in position. Horizontally directed slots formed in the base plate along one longitudinal edge thereof cooperate selectively with tabs on the lower longitudinal edges of the housing to lock the housing on the base plate selectively in either of two positions. Screws or rivets may be used as additional fastening means for the base plate and housing.