I've wanted to add a catch cup to my mod but the finishing washer was too big for the top of the box. Looking around Home Depot I found something that I believe looks and works great.
The 510 connector is a perfect fit in the sweat tube so it's an easy mod to cut it down to fit whatever mod you want to install it on.



The 510 connector is a perfect fit in the sweat tube so it's an easy mod to cut it down to fit whatever mod you want to install it on.