Features H2Optics Technology for reliable, hands-free operation Manual mechanical override button allows manual flushing if battery power is temporarily unavailable 1 1/2 Inch top spud, 11 1/2 Inch high and 1 Inch inlet Factory set to 4.2 litre @ 60 psi (1.1 gpf @ 414 kPa), not field adjustable Battery Flush Valve