If you need to drain your Worcester Bosch boiler like I did recently then this might prove useful.

It's an exact fit (see pictures), if you want a loser fit then scale up slightly. I've included space to fit a 4mmx2mm magnet so you can hang it on the side of the boiler, just like the pictures. Personally I think its better just left fitted but if you're a boiler engineer you might prefer to use the keyring hole.

I used PLA but use whatever you want. I used the strength preset in Orcaslicer.