Riser pipes in rigid PVC allow you to connect from a sprinkler line, typically under the ground, to a hose faucet, drip manifold, shrub head, spray head, impact sprinkler, or gear-drive rotor. The wall thickness of PVC risers is thicker than Schedule 40 pipe which means it has greater rigidity and pressure rating. As plants grow, you can extend the riser above the plants via addition of a Schedule 40 PVC coupling and another riser. Use a support stake to stabilize taller risers. Riser inlet/outlet sizes for residential applications are 1/2-in., 3/4-in., and 1-in. male pipe thread (MPT), with lengths spanning from just the pipe threads (close nipple) to 48-in. Compatible with irrigation components from Orbit, Hydro-Rain, and other major brands. For outdoor irrigation use with cold water only.