I have always been annoyed by the size of electrical panel keys. In my line of work, I need one with relative frequency. However, keys that come with panels are much too large for a key ring. This design aims to remedy that problem.
I have been surprised at the strength of the key, but a seized panel can warp the plastic if you're not careful. Luckily you can print a few spares in a matter of minutes!
Monoprice Maker Select Plus
I recommend printing this at 100% infill at the smallest layer height you can for maximum strength.