OVERVIEW: The DD PLUS is a versatile double disc swing check valves use spring assisted half-discs for up to 66" sizes. The wafer ends fit between ANSI 125/150# and Metric PN10/16 flanges. It is suitable for frequent flow reversals, but not fluids with solids. Includes many special features, including lead free and NSF certified for potable water applications. Meets AWWA C518 requirements, UL and FM Approved. 2" to 66" diameters.