The 9095A AST Overfill Prevention Valve is installed at the fill port of an aboveground storage tank. Used in a tight fill application, the valve terminates flow of product when the liquid level reaches a preset warning level (90-95% full). The valve is installed on a standard N.P.T. male connection when used with the quick disconnect or female adaptor. When installed to manufacturers requirements the Overfill Prevention Valve can eliminate environmentally hazardous spills. A built-in bleed hole also provides anti-syphoning protection. ULC Listed.