Summary

Fits the aquarium coop 1 inch bulkhead. May need to use plumbers tape to prevent a slow leakage.

https://www.aquariumcoop.com/products/aquarium-bulkhead-fitting-slip-x-slip?variant=40053053325381

It's not pretty, but it gets the job done.

I printed in PETG for my bulkheads. 100% infill, haven't tried any less.