Our swing check valves are designed to prevent backflow. The clapper is spring loaded allowing the check valve to be mounted horizontally or vertically. Specifications: 200 PSI rated Opens at 2 PSI Spring Loaded Download Spec SheetTabsPart Table Part Number Size Finish SPCV1/2 ½" F NPT x ½" F NPT Brass SPCV3/4 ¾" F NPT x ¾" F NPT Brass SPCV1 1" F NPT X 1" F NPT Brass SPCV125 1¼" F NPT X 1¼" F NPT Brass SPCV15 1½" F NPT x 1½" F NPT Brass SPCV2 2" F NPT x 2" F NPT Brass