That's a special, fancy dedicated TPR discharge tube. I see them all the time on manufactured home water heaters. They come with the galvanized fitting at one end. Jodi, PEX is the standard plumbing pipe in new construction out here. Has been for quite some time. It works great. Image Insert: 40.2 KB Image Insert: 33.93 KB - Jim Katen, Oregon It appears that the end of the TRP tube is blocked by some insulation material