Features: -Piston assembly, cylinder, gears are V2 compatible (standard) -Extremely strong machined upper receiver -Crisp selector switch -Lightened trigger spring for better pull -Low profile pic rail -full threaded barrel (not the weird half threaded p90 barrel with cross threading issues) Upgraded with: -Quick Change Spring (go from field to CQB fps in seconds) -Mosfet wired for higher ROF and trigger response -Deans/T plug wired, but Tamiya adapter available on request -Reinforced radiused V6 gearbox (same front profile as V3 gb, which is far stronger than V2 gb) -semi-auto issues, could use an M-trigger Battery, extended backplate, rail system, and other add-ons available