Product details:

Auto-Drain provides completely automatic 12-volt push button operation of the valves that dump your RVs grey and black water holding tanks. It mounts onto the slide valve of a 3 or 1. 5 conventional waste valve and no plumbing modifications or difficult clamps are required. Works with Valterra and Bristol 3 and 1. 5 waste valve models (not included). Auto-Drain Valves are made of corrosion-resistant steel, aluminum and plastic. Before installing, your holding tanks should be emptied. There is an open or close cycle in less than 4 seconds for the 3 models. Included with the Auto-Drain Valve is a mounting bracket, rocker arm switch, switch box with light (indicates open or closed valve) and complete installation and operating instructions.Voltage: 12V DC
Amperage: 200 mA
Cycle Time: 4 seconds for 3" model
Compatibility: Valterra and Bristol 3" waste valves (not included)