It is a small grille used to protect the water faucet's outlet and prevent small animals from entering it, which might get trapped and clog the faucet.

Depending on the faucet you are using, you may need to adjust the size of the grille, as your faucet may have a different diameter.

It's made of PLA, but I think it can also be made of PETG, TPU, and ABS.

If it's loose, you can use insulating tape or masking tape around the edge of the faucet to make the grille more secure.