These shelf stops / clips are made for an Avallon mini fridge. They keep the shelves from falling out when extended.  Specifically, I've used these in my 140 can beverage cooler for my mini bar.  These clips enable you to remove the rear metal guards so you can fit more cans.  I use these in combination with a spring drink caddy in my mini bar.

The clips act as stops and prevent the shelves from falling / being pulled out.  All you need to do is snap the clips on, no tools required, they use spring force to locate to the existing drilled screw holes.