The optional PWRX™ Long-Life Battery System features advanced battery and electronics for a 10 year battery life to reduce the downtime and maintenance costs associated with changing batteries. Pressure Compensation feature ensures accurate flush volume regardless of inlet water pressureSelf-Cleaning Piston with integral wiper spring significantly reduces clogging and maintenanceDezincification Resistant semi-red brass alloySelectronic Proximity System with universal sensor provides hygienic, "hands free" operationState-of-the-Art Electronics prevent ghost flushingFully Mechanical Manual Override Button can flush the valve without powerFail-Safe: Valve automatically closes upon loss of power or water pressure and does not need to be reset