I designed this box to work similar to power-tool boxes. It uses 2 sliders which are used to lock the box and to fix it to another box.

Use the “Stackable” file if you want to stack multiple boxes. The stackable boxes need the "foot-connector" which is simply snapped into position.

Print a left and a right slider. Use multi v13 for stacking boxes and single v9 for a non stacking box.

The sliders have the following Positions:

Inner Position    - Box is closed and upper Box is attached
Middle Position - Box is closed and upper box can be detached
Outer Position   - Box is open and upper Box is attached