The ramped top edge makes it easy to slip the shelf onto the clip, but more importantly makes shelf removal easy.  No need to depress prongs or stays to remove the shelf.

US Patent No. 4,909,465

Specifications:  Furnish Ly-Line Shelf Securing shelf clips for all adjustable shelves.  Clips shall be molded of high density clear polycarbonate.  Clip design shall incorporate double fluted pins and double depressing grip cams.  Fits into 5mm holes drilled into cabinet sides at 32mm on center,  allowing shelf adjustment of 1-1/4 inch.  

Exclusive shelf clip is designed to restrict shelf from sliding out of the cabinet and to keep shelf from collapsing or damaging shelf clip holes when loaded.

There were two sizes of clips manufactured, fitting drilled holes measured 1" or 1-17/64" (or 32mm) from the center of each hole.

1" Inch Centers - for pre-1983 Projects

Quantities are very limited as these ceased production in 1983

US Net:  100 pc bag:   $110.00

32mm Centers - for projects after 1983

US Net:  250 pc bag:   $185.00

US Net: 1000 pc box:  $495.00

The design of the clip and the pressure from the prongs keep the clip firmly positioned against the side of the cabinet unlike single peg clips which have a tendency to tip and ruin the shelf clip holes.

Same size fits 3/4" or thicker shelves