These look like old style "signtech" clips. IDK if they are still made. Reece Sign supply has them listed on their site but it says "call for availability". Also, IIRC signcomp bought out signtech (some time back) and has the rights to their old items so check with signcomp. And it's a shame but just last week we discarded an old frame than had a bunch of these. Later this afternoon I'll check my stores (I'm king of the pack rats) to see if I have any. How many do you need?