I recently relocated a couple of my printers to this shelving unit which is out of my immediate work area but I needed some tool organization to so I don't have to run back and forth for things like filament snips or Allen wrenches. These are simple cup-type organizers that are designed to fit on the inside of a support leg of a bolt-less shelving unit. Specifically, they were modeled for use on this shelving unit: 

https://www.uline.com/BL_3867/Wide-Span-Storage-Racks-Particle-Board

They should work on most shelving units of this style provided they have a 1 ½" space between slots. They can also be used on the outside of the support leg. The design originally had 4 pegs to correspond to the 4 holes in the immediate area of the mounting point. After some prototyping I realized that 4 pegs were overkill and could get cause the part to get stuck if the print was even slightly off.

Supports = Very Yes.