The Hoffman 79 Straight Water Main Vent Valve is designed for hot, cold, or glycol water mains in process applications with specific gravity greater than 0.7. With a pneumatic bell for discharging moisture, it has a built-in check valve, 1/2-inch NPT female and 3/4-inch male straight shank. Removable top is tapped for 1/8-inch NPT safety drain connection.