The 4" 475BG Reduced Pressure Principle Backflow Preventers with grooved end butterfly valves and integral supervisory switches are utilized in high hazard, potable water applications to protect against both backsiphonage and backpressure. The Model 475 is shaped in the n-Pattern, and is used in vertical flow up and vertical flow down applications, often for new or retrofit installations in compact spaces. Its single access cover reduces maintenance downtime and repair costs and is equipped with the patented, center-stem guided Compound Check for low headloss, superior reliability, and unmatched performance.