A cover/guard for a rocker light switch. Works with standard rocker switch face plates with #6 screws that are 2-3/8" apart. Similar to products such as https://www.amazon.com/Lisols-Mind-Switch-Guards-Security/dp/B07RBTMG78.

The screws that came with my face plates worked fine, although you may need slightly longer #6 screws.

If you lay it on it's side while printing you can print without supports.