Duo-Chek high performance non-slam check valves are the original Mission Manufacturing Company wafer check valves introduced to the market in the late 50’s. The valve is available in the sizes, pressure classes and configurations required to meet the most demanding of applications. Duo-Chek valves have long been the standard for low-pressure drop flow reversal protection. These valves are made from cast iron, cast steel, stainless steel, and a broad variety of exotic materials. Duo-Chek offers retainerless designs to API 594 end-to-end dimensions in steel bodied wafer and lug style with a wide variety of trim materials including both metal and resilient seats. Valves come in sizes up to 88″ and pressure ratings up to class 4500.