Selectronic Concealed Sensor-Operated Toilet Flush Valve Base without Power SupplyThe Selectronic concealed sensor operated toilet flush valve from American Standard helps to save the most water, with a maximum flow rate of 1. 1 gallons per flush, without sacrificing performance. A convenient proximity sensor makes using the toilet flush valve easy, clean, and effective. This flush valve is designed for use with wall hung toilet bowls with a 1 1 2" exposed back spud. The valve has self cleaning piston operation with integral wiper