License plate suction cup interface thingy

thingiverse

I wanted to show off my vintage license plate on the rear window of my '71 Camaro, so I bought some 30mm suction cups with hooks attached to them. They cost about $5.00 for a package of 12. It would have been possible to just use the suction cups as-is to stick the license plate to the inside of the window, but I didn't like the hooks. So, I removed them and even that might have worked since the little knob on each suction cup has a diameter of about 8mm, which is just slightly bigger than the short side of the oval holes in the license plate. To keep the suction cups from coming loose through vibrations or temperature changes, I needed something to lock them into place. That's why I designed these little gadgets in Tinkercad in no time.