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 opens and is fully open at 10% over pressure. Unlike non-pilot operated units that requires substantial over pressure in order to obtain full lift. On the model 1049 the blowdown is limited and the valve reseats at set point, where the non-pilot operated units will go below set point in order to reseat. When non-pilot operated vents stay open longer to reseat, additional venting of tank vapors occur and possibly N2 consumption rises. In addition to this feature, the Model 1049 does not allow back pressure in the connected header system to effect the set point of the device like a weight loaded device. The pilot controlling the opening of the vent is independent of the header pressure and eliminates this problem. It should be noted that if the header pressure is higher than the tank pressure the free floating pallet design of the model 1049 will not allow the pallet to open therefore preventing possible back flow into the tank.