These two brackets support a Stanley Storemaster storage box slide underneath your desk like a drawer. I couldn't find a desk drawer big enough, and was given a Storemaster for Xmas, so this happened.
Notches in the brackets lock the box in place so it is difficult to knock out onto the floor accidentally. The box can be stowed with the stacking/transport clips folded down, which makes it quicker to get into, but it is easier to do the installation with the clips closed.
Print both brackets (no support needed), remove the tiny built-in support tabs from the notches, and screw the brackets into the underside of the desk with 4 off 8ga 25mm (1") screws. Use the box to provide the right spacing. The bracket is about 9mm thick, and if your desktop is thinner than 18mm use shorter screws so you don't go right through it!
To use just slide the box in between the supports until it clunks into the retaining notches. To get it out, lift the box up slightly, and slide it back out again.
The author marked this model as their own original creation.