Overflow Stopper

This is a thing to block the overflow hole on a bathroom sink. Obviously this only fits round holes, but it can be scaled to fit different sized round holes.

Why would you want to block the overflow hole on a sink? If the trap (u-bend) has become blocked so that the sink doesn't drain properly, one solution is to use a sink plunger. Do this without blocking the overflow hole, and you end up with a jet of foul water that typically hits you in the midriff. Block the hole by holding a normal sink plug over it (say) and, often as not, it slips and you end up with a finer jet of foul water that hits you in the face.

This locates firmly in the hole and, even if water gets past the O-rings, the flange will prevent it from squirting straight at you.

The O-rings themselves aren't meant to be printed, though they could be printed in a flexible material, obviously, or you could print them in PLA and use them to make moulds to cast silicone sealant in to make soft silicone O-rings. Mos