The new G&G G2 system has arrived to bring a new level to their AEG line up. The G2 system is a newly designed gearbox built from the ground up by G&G. It has numerous features to give it a cutting edge in today's airsoft market. Everything about this gearbox is built to be durable, high performing & pushing the envelope of features offered to players. Here are some highlights below: -  double o-ring air nozzle -  thicker cylinder head -  new ETU/mosfet w/sound indicator for low battery - redesigned bevel gear - quick change spring - power cut off from magazine removal/empty Muzzle Velocity: 380-400fps Build Material: Mostly Metal, polymer furniture. Battery Type: 11.1v 1000 MaH LiPo Stick/ Numchuck