The racks are 1 "PVC, and the cross ties are 1/2" CPVC. The clamp widget uses curved washers to grip pipes, but I'll probably do something more elegant. In this installation, the spring pins are captured inside the PVC fittings. I think the hole is large enough for most springs if it is ever needed. Another option is to cut notches in PVC to capture the TT deck at the edge.