This 1/2 by 1/2 in lead free dual check valve prevents the reverse flow of polluted water from entering into the drinking water supply at the service entrance or at individual outlets. It is designed with a longer lay-length tailpiece to be backwards compatible with the previous versions of the watts no. 7 valve. This valve consists of a lead free brass body construction, with two plastic replaceable check valves and stainless steel springs. It is designed for non-health hazard residential water system containment, continuous pressure applications and is to be installed immediately downstream of the residential water meter, in a vertical or horizontal position. The minimum working pressure is 10 psi.