these have an upgraded 8mm Version 2 Gearbox featuring the electronic trigger and quick-change-spring system

When not in use

and Cylinder / Polymer Stock

Infinity Diamond Open Slide kit w/ comp red/gold

at bottom and in center of housing to ensure the hopup unit is exactly centered

SS Airsoft Custom AEG - Terminator P90 AEG (Black) AIP these have an upgraded 8mmFeatures Laylax Type Triple Rail System Installed with Laser Engraving Marking Laylax Type Box Magazine installed with M4 Hicap magazine included Matrix 150mm Mock Silencer Polymer Body with Metal Receiver Gear Vibration Dampener Convertible Barrel Metal Barrel Assembly, Gearbox, Receiver, MIL STD M1913 Style Rails, Flash Hider, Charging Handles Adjustable Hop Up Box Magazine Instructions: Open the lid of the M4 magazine included. Insert it in the M4