This is a mount for putting an inexpensive battery disconnect or safety cutoff switch behind a panel. Useful for a battery box for example.

I had to trim my first attempt a little, so I have made the center hole a little bigger and named it 52mm.

The flange is 2mm thick, the standoffs an additional 17mm (IIRC). They fit a 9mm hole in the cutoff switch and have a 5.5mm hole through them.