Magic Plastics CR2 Corrosion Resistant Check Valve, 2" - 0801-20H2 Back-Flow prevention check valve is 100% corrosion resistant. This check valve is the ultimate solution for protecting your expensive Heat Exchangers from the potential damage of inline chlorinators, all while maintaining a full-flow circulation system. The CR2 has a 1-1/2 lbs spring-loaded gate and 100% silicone gasket. The Spring-Loaded gate mechanism assures Full-Flow with minimal cavitation and a positive water seal when in the closed position. In addition, this feature allows the valve to be installed in virtually any orientation. Longevity, serviceability and Magic Plastics' quality make the new "CR" Valve the ideal choice for highly corrosive conditions as well as any installations requiring the need for back flow prevention.