Description Male thread, “mushroom” style top design emergency vent made of heavy duty cast iron, (aluminum base available). Top acts as weather deflector and minimizes the chance of theft or vandalism. Machined top & base with Buna N “O” Ring provides a vapor resistant seal. Recommended Accessories: AST Overfill Prevention Valve AST Spill Containment Box AST Sight Gauge AST Audible Alarm
