Designed this to hold the device side of an USB extension cord.
The USB plug is 25mm long, 9mm thick and 16.5mm wide. The bend protection is 4mm wide and the cable is 2.6mm wide. Maybe it fits other plugs, too.
I use this to put my Logitech Unified Receiver into a more convenient location.
The Roof of the holder involves some bridging but my printer did succeed printing this without support.