I needed to add an USB light strip but wanted it to be switched. Most switch boxes out there require to be bolted on and I didn't want that.

Boxes made to fit the rails on my Ender 3 V2 - so it may fit others

One model for rectangular rocker switches (30mm the long way - same as stock power switch)
another one for round rocker switches (20mm diameter)

Wire access through bottom rail, depending on wire size, you can clip of a section of the rail without compromising integrity (see pics - I had to do this to fit my wires)

These printed fine without supports, but may need a bit of filing on the un-supported end for the lid to fit snug.

Hope this helps!

Creality

Ender 3

Doesn't Matter