Everlasting 1-1/4" flanged steel slow opening, lever-operated boiler blow down valve with a primary service rating of 300 psi and a maximum blow-off service rating of 485 psi. The Series 4061 valve operates by having the line pressure and heavy spring hold the disc firmly against the body seat sealing off the flow. When operated the disc slides across the body seat pushing harmful boiler scale away, and wiping clean the precision lapped surfaces.