Flapper bends over a radius, no sharp 90° edges—lengthens life of flapper hinge. PVC plastic check body, ultrasonically welded and can be solvent welded for rigid pressure rated piping systems to 25 PSI - (57 ft. of Head) at 130°F. (30-0182). Vertical or horizontal installation. Slip x Slip for 4.3 PSI (10 ft. of Head) at 130°F. Avoid more than 10 ft. static head above the check valve. Designed to reduce water hammer.