This is a through-hole style mount for an Amphenol AT04-type connector (tested with AT04-2P). A backface mounting ring is also included in the print files, although usually not required especially if using washers for the mounting bolts. 

Designed for 5x M3 bolts to flat-mount, with the connector passing through a pre-drilled hole (approx 18 mm diameter). 5x mounting bolts is probably overkill and 3x would be fine.

I used this to mount a connector for the horn on my '99 Wrangler when converting to a aftermarket removable steering wheel. 

Printed a on a Prusa 3 Mini with PLA.