Abstract: Knockout window means include a knockout port formed primarily in a sidewall of an electrical assembly box and a knock-out panel superposed over the knockout port from the inside of the sidewall. The knockout panel is attached only at its front and back ends to the box, the front end being connected to the inside surface of the sidewall and the back end being connected to the backwall, each by a frangible web which provides doubly accessible panel removal slot means between each end of the knock-out panel and the structure to which each is attached. The panel removal slot means are accessible from both the outside and the inside of the assembly box at each end of the knockout panel, and include four pairs of bearing surfaces against which a wedge-like tool may bear for applying twisting leverage to fracture the webs.

Abstract: A screw mounting clip member is adapted to be slidably fixedly engaged in a slotted aperture adjacent an unthreaded screw-receiving borehole. A spring detent member provided on the clip extends into the borehole when the clip is fixedly mounted in place. A threaded screw is fastened in the borehole by initially being manually thrust endwise into the borehole without turning, thereby deflecting and forcefully engaging the spring detent with the screw threads. The screw may thereafter be tightened by turning the screw against the spring detent and may be unfastened only by reverse turning of the screw, in the conventional manner.