Glue shut off valves(also known as cpvc shut off valve) are commonly installed on the water lines where CPVC pipes are used. Before and/or after the hot water tank, before and after the water meter, and various other uses.
Glue shut off valves do not have the standard 3/8" connection (New Product: these are available 3/8" glue shut off valve) required to connect to kitchen and bathroom sink faucets with standard supply lines.
Under kitchen and bathroom sinks the most common water shut off valve would be a 1/2"x3/8" compression stop.
When installing a glue shut off valve, be sure to have the valve in the open position when you are gluing the valve on to the pipes.
If you glue the valve to the pipes with the valve in the closed position it sometimes glues the valve shut and you will not be able to open the valve.
When gluing cpvc pipe and fittings be sure to use glue and cleaner labeled for cpvc pipe. Also remember to allow the glue to dry before turning on the water, be sure to read the can of glue for the recommended dry time.