Zurn 1-950XLT Wilkins Top Access Double Check Valve 1-Inch Backflow Preventer Easy maintenance with both checks pointing upward Fits within standard meter boxes Nary replaceable seats and silicone rubber check disks Entire unit serviceable in line A tried and true design favored by installers worldwide Ideal for use where Lead-Free valves are required. Designed for installation on potable water lines to protect against both backsiphonage and backpressure of polluted water into the potable water supply. Assembly shall provide protection where a potential non-health hazard exists.