Summary

A cap for Arm & Hammer detergent jugs and a coupler for bottle pumps.

Why? Not sure; I figured I'll make the cap now and figure out a purpose later.

I've tested the cap, and it has a watertight seal, but your mileage may vary.

The caps come with modeled supports; break them off after printing. Also comes with non-supported versions. I've experienced some overhang issues with the coupler because of how it's sliced. It is just a little messy on the inside - but it doesn't affect the effectiveness of the coupled handpump.

See https://youtu.be/wzgvPpAAZh8 for notes and water-tight testing.