Just push a switch on the Barker 3in Valterra-Bristol Model Auto Drain to dump your RV's black and grey water tank. Eliminate hassles with hard to reach and difficult to operate valve locations. Easy, manual operation in case of battery failure or valve problems. No additional plumbing fittings to install - none to remove. Constructed of corrosion-resistant steel, aluminum, and plastic. Holding tanks do not have to be dumped to install. Also fits Valterra and Bristol slide valves. Each Auto-Drain comes complete with rocker arm switch, switch box, and complete installation and operating instructions. Voltage is 12 volts DC, amperage is 150 mA, and cycle time is 3 seconds. Also comes in 3in model.