Hayward Threaded Pressure Reducing Pressure Reducing Control Valve, 3 4 in Pipe Size PBV2075TPE1 Toilet Paper Type Multi Roll Removable front panel for easy Removable front panel for easy cleaning Bathroom stall door includes patented patented permaseal seamless design providing patented permaseal seamless design provides superior door integrity against water penetration to stop doors rusting from the inside When the valves preset pressure is exceeded (model has an adjustment screw that you can adjust in the field) this HAYWARD pressure reducing control valve can apply back pressure to a metering pump to help prevent siphoning and eliminate variable dosage rates due to a fluctuating downstream pressure