Yep, pain in the butt. The 3/8 tub is 6.35mm, or .25" ID. 9.1mm, or 0.358268" OD. I'm gonna take my cross connector and a grommet to Lowes and see of they will fit. If not just have to get from them, or shop that sell their tubing. It's only a few $ difference so not end of the the world. I have a 10% code that as of now still works.Pretty sure autopot stuff is metric. I had a hard time finding any replacement stuff that fit them that didn't come from autopot