Electrical, gas and water meter boxes are often held shut with a plastic latch that uses a
triangular key. If the latch is broken by an overzealous meter reader you will need this as a replacement.

If you've lost the little retaining ring, print the “Meter Box Latch With Threads” and the “Meter Box Nut M10 4mm”.  The nut is smaller than the a standard M10 nut so it will fit inside the hole in the meter box door.  Use small flat head screwdriver to turn it into place.

I've also included a triangular key that fits any standard meter box latch.

You'll want to set small perimeters to print very slowly and turn on the fan as you need to be sure that one layer is cool before the next layer is started for the small triangular pillar.