This is intended to prevent fingers from entering a bulb socket where you didn't put a light bulb.

Easily screw in/out using a coin or a screwdriver.

Why you don't just put a light bulb in there is up to you, but now you can put this cap/plug in instead!

Strongly suggest printing in PETG for heat resistance.

Don't be dumb, this doesn't offer any weather/water proof protection for an exposed socket.