The dual solenoid design of the F2™ provides the same functionality as the legendary Fusion Engine™ but in a more compact, efficient and flexible design. Dual solenoids allow for the nozzle and the poppet valve to be adjusted independently of each other for unparalleled control over both the loading time and air volume used. Additionally, this makes it possible to change the firing sequence giving it the ability to operate in both true closed bolt as well as "AEG" mode.The F2™ incorporates a new one-piece, lightweight poppet valve design yet still operates on the same principle as the Fusion Engine™ poppet. This valve is able to operate at lower pressures and uses less air volume to function which optimizes air efficiency.
Source: PolarStar Airsoft.