Hydroponics Bulkhead / Drain + Hose coupling for 4" PVC

Bulkhead fitting contoured to the shape of a 4" PVC tube for a better water seal.

Will update the description with the o-ring sizes that I used.

My other 4" PVC pipe designs:
[Hydroponics 4" pipe clamp for use with 3mm paracord](https://www.thingiverse.com/thing:2555658)
[Hydroponics Net Cup / Pot System for 4inch PVC Pipe](https://www.thingiverse.com/thing:2474497)