Fluidmaster 400LSRP4 Leak Sentry® Toilet Tank Fill ValveSave water and prevent a running toilet with a Leak Sentry Toilet Fill Valve. This revolutionary toilet fill valve includes a water saving roller clamp to make sure that the right amount of water goes into the bowl with every flush. Its also the only toilet fill valve with active leak detection, preventing a toilet from leaking without the homeowner having to take any special action. Best of all, when theres no leak in the tank, it works just like a