This 6 IN double check detector assembly prevents backflow of non-health hazard fire protection system substances from being pumped or siphoned into the potable water supply. It incorporates a gallons per minute meter to detect ground leaks and unauthorized illegal taps, greatly reducing annual water expenses. Its compact epoxy coated cast iron unibody and modular check design facilitate simple and easy installation and maintenance. Maximum working pressure is 175 psi (12.06 bar).