Series 3000SS Double Check Detector Assembly Backflow Preventers are designed to prevent the backflow of fire protection system substances from being pumped or siphoned into the potable water supply. It consists of a compact construction and short lay length, ideal for retrofit installations. It features a lightweight stainless steel body, thermoplastic and stainless steel check valves, and low head loss. Series 3000SS can be installed in the horizontal or vertical flow-up positions. It is designed for installation on applications identified by local authorities as non-health hazard, such as on fire protection systems. Maximum Working Pressure: 175psi (12.06 bar).