I visited 5 different optical shops near my home looking for clip-ons for my multi-focal glasses.  None had any that fit nicely.  They had a couple that fit badly and wanted $50 each for them.  No thanks.  Two shops had "custom made" clip-ons at a cost of $150 and $175.  NO THANK YOU.  I ordered these from Amazon they fit great for a fraction of the cost.  They also look rather stylish.  The only thing is I wish they weren't flip-ups but I won't be using that feature.  From the front you can't really tell they are clip-ons unless you are less than a couple of feet away.  From the side, you can see the gap between the glasses and the clip ons if you are close.  But I am happy with my purchase and recommend these.  The lenses of my glasses BTW are approximately 56 mm by 34 mm and the 58 mm size clip-ons fit great.  See pics.  They also have rubber feet which will not scratch my expensive lenses.  Good!