The Cr 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. The Numerous Features Are Included With The Cr Valve Including A Proprietary Designed Hastelloy Spring, Glass Filled Noryl Injection Molded Shaft, 100% Silicone Gasket And Clear Serviceable Lid. Also Equipped With A 1/2Lb Spring-Loaded Gate Allowing It To Be Installed In Any Orientation.Replacement Option For: Ai # 4-25-0111 / Mfg # 0802-20 Specifications Category: Plumbing Subcategory: Valves / Valve Parts 0801-20H