Wolverine Airsoft Inferno Gen 2 owners can watch this video showing how to do the M4 conversion from an AEG into an HPA-powered airsoft rifle that includes the Spartan Kit... "The INFERNO Gen 2 features a revolutionary single solenoid, independent poppet and nozzle design that sets a new standard for a drop in kit. Particularly, it is designed to solve the “open bolt problem”.