Febco FRK 850 870V SM2 8 Part of the RK 850 870V Series chat hdpe and other service vehicles and other service vehicles This 1 1 2 inch lead free reduced pressure zone backflow preventer assembly with its exclusive design incorporating the patented air in and water out principle for protection during an emergency condition prevents the flow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements This spring module kit is used to repair the second check spring module of a 8 to 10 inch reduced pressure zone assembly All parts are genuine and original to the valve