PolarStar F2 Engine – Custom Colors by Monk CustomsThe 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. Custom anodizing colors, exclusively available from Monk Customs **All kits come with a Filter Fitting installed, FCU,