Cardboard Box Corner

These little doodads are designed for 2mm thick corrugated cardboard boxes. They will simply keep the flaps open vertically, for example to make a quick and dirty spray booth.

Every other model I found was designed to keep the flaps folded back (for packing or storage) and the inside space was far too big. These are designed to be a tight fit — the inside is exactly 2mm, just like the cardboard.