Airbrush Holder with Stackable Box

I designed airbrush holder that can be laid out side by side for as many units as you need, or put each unit in the box and stack them vertically. The box should stack fine without magnets but there are holes meant for 6mm x 3mm magnets. The airbrush holder itself is designed primarily for Iwata airbrushes but should work for many other airbrushes. The area for the main body of airbrush can accommodate up to 12.5 mm (about half inch) in diameter. In addition to single airbrush holder and box, in