Aluminum mock suppressor fitted into the handguard

3 different hardness (50°White/60°Red/70°Black) for selection

and a quicker change spring system

ADJUSTERS: POM Thermoplastic

PolarStar F1 Centerline HPA Engine for V2 Gearbox Airsoft Rifles Airsoft Gas Rifle Aluminum mock suppressor fitted intoM4 M16 What is the F1? Like the Fusion Engine and JACK, the patent pending F1 is a high performance HPA (High Pressure Air) system which replaces the traditional piston and gears of an AEG with a programmable pneumatic system. Flow Control The unique flow control system uses an integral check valve to regulate the forward speed of the nozzle while maintaining the fastest retract speed possible. This system is also what makes the F1's "2 stage" firing