B&E Productions show how to take the gearbox of the M4 Matrix Sportsline AEG as they assemble and reassemble this AEG. This AEG is part of an affordable line available at Evike.com under the Matrix brand with S&T Airsoft being the OEM... "In this video, Ethan shows you how to take the gearbox out of an Airsoft M4. He is using a Matrix Sportsline gun as a model."