These are hard to find.  They're exactly what they're supposed to be.  However, I needed them for the larger diameter pegboard hooks, and these are sized for the smaller diameter.  I solved the problem by mounting a large diameter hook in my vise, and placing a lit candle underneath it to heat it and keep it hot.  Then I held each hook over the hook long enough to melt the plastic a bit and to deform it to accommodate the larger diameter.  A little fussy, but it worked.