The “CR2” Back-Flow prevention check valve is completely corrosion resistant, making it the ultimate solution for protecting your expensive Heat Exchangers from the potential damage of inline Chlorinators while also maintaining a Full-Flow circulation system. Numerous features are included with the “CR2” Valve including a proprietary designed Hastelloy Spring, Glass-Filled Noryl injection molded shaft, 100% Silicone Gasket and a Clear, serviceable lid. The “CR2” Valve is also equipped with a ½ lb. spring-loaded gate, allowing it to be installed in any orientation.