The Model 1049 offers the best pilot-operated vent technology on the market today. The unit allows for bubble-tight seat leakage until the pilot starts to exhaust. At that time, the vent starts to open and is fully open at 10% overpressure. Unlike non-pilot operated units that require substantial overpressure in order to obtain full lift. On Model 1049, the blowdown is limited, and the valve reseats at the set point, where the non-pilot-operated units will go below the set point in order to reseat.