This is a locking clip, designed to keep a shelf bracket for wire shelves from coming out of the vertical rail. Specifically, it fits in the slots of vertical rails for Home Depot's Everbilt Heavy Duty wall shelving system.

Having just installed some heavy duty wall shelves in my storage room, I noticed that with the proper upward force, I could too easily dislodge an installed shelf. This could be dangerous.

So I designed this pin to fit in the slots above each bracket. I was, frankly, surprised I couldn't find something like this out here already.

Print one for each bracket, and press in place to keep your shelf brackets locked in place, so they can't push up and slip out.