The progress of the PolarStar Airsoft Fusion Engine for the M249 AEG is humming along as the photo above show what seems to be pre-production version of the drop-in gearbox replacement to use HPA as power source. This also means that those who have been waiting for this won't be waiting for long. Other users have already used other Fusion Engine versions just to do their own modifications like what is shown in the video. This means that not much modding now once this gets released.