The cooperating clip, shown generally at 20 has a flat shelf supporting surface 21, preferably formed with two bifurcated fingers or prongs 21a and 2112, with the open 3,097,822 Patented July 16, 1963 end of the slot 22 formed between the two prong-s 21a and 21b providing space for a nail, screw or bolt or other attaching means (not shown), for [firmly attaching the clip to the shelf 40 (FIG. 5),