Pantene pump shampoo coupler ring

Coupler ring to connect two Pantene pump-style bottles together so one can drain into the other.

I found another [shampoo ring](https://www.thingiverse.com/thing:2185329) on here, but even if scaled up, didn't work with these bottles, so, I made this one. It was inspired by the other model, but I started from scratch.

Update (Jan 17, 2018) - The first ring I made broke when being tightened down on the next bottle pair we joined up. The walls were a bit thin so I increased the outer diam