This is a replacement switch for a heated-pad - may be similar to heat-blanket switches.

3D printing makes this a much better part than the original injection molded piece - which, as you can see in the pics - had very little plastic left-over for twisting the switch on and off.

Print upside-down (slots facing up) with .2mm layer height and supports. The supports should pop-off leaving a relatively clean finish.

This is a very snug fit - but holds better than the original part and looks better in red!

Hopefully the design helps someone else fix what would be another throw-away item because of a small plastic part.