Mirror Hanging Hardware

I'm looking for hardware to hang posters that are on rectangular CorePlast. I think there is something like plastic corner brackets that you can put on the corners and screws into the wall. I think they probably originally intended to hang mirrors. I want those plastic, not metal or anything else that would not clear because they can cover a little work on the posters and it would be necessary to show through. I searched the internet and can find the smallest that you put on the sides, top and bottom mirrors, but I would really like to get the corners. Can you tell me where to find them and how they are called?

You are looking for "frameless mirror clips. Most are designed to go on the sides, but they are made to go into the corners as well. I have others who understand both. For a mirror, you're supposed to use the corner clips and fasteners side because the weight of the glass, but I think you should be fine with coroplast all corners.

You should be aware that even if the clips are "clear", I would not call them transparent. They allow the color of the background through, but you can see that the clips are there.

If you really have no chance of finding them, email me and I'll see if we can work something out.