and 3 compression springs on top

Mock bolt catch for easy hopup adjustment

or can be flipped down to allow you the use of a magnified scope or dot sight

The F2 incorporates a new one-piece

Structured and Padded throughout to protect your HPA Tank from field elements

PolarStar F2 HPA Engine for V2 Gearbox Airsoft Rifles Trigger Electronics and 3 compression springs onWhat is F2? F2 is essentially a Mini Fusion Engine. It offers the same adjustability and performance as the Fusion Engine in a cylinder sized package. Patented Dual Solenoid Design 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