Box of 1-1/2″ Schedule 40 PVC Pipe Fitting – Coupling – Slip x Slip Slip Coupling for Schedule 40 PVC Pipe (Slip x Slip). Slip couplings are used when the pipe doesn’t need to be taken apart and you are simply joining two smooth pipe ends together. Both pipe ends are glued into the coupling, forming a joint. byJuly 4, 2026