The connection between two 12V DC power cables has the issue that it comes apart with the slightest tug. This solves it.

• It is held shut with M3 bolts.
• Adaptable length
• The max thickness of the cable is 12 mm (see figure).

A 12V DC power cable (5.5mm, Type M, Barrel) is common cable seen in equipment that needs a bit more juice than a USB, ranging from routers to telescopes and back massages. It's a cylindrical coaxial cable.

Note on Blender file: I am a novice at blender and messed up the scale (export with scene scale is 550%)