Internally, the gun has a 9mm bushing gearbox, a brand-new electronic control system, inline mosfet protected trigger contacts, 6.03mm tightbore barrel, and a quicker change spring system. Program the electronic control system to shoot at 3 to 5 round burst. Additionally, the ECS has motor protection and low battery detection to help protect the airsoft gun in the long run. It will shoot 330-360 FPS using 0.20g BBs and 900-1000 rpm using a 9.6V battery. Unfortunately, the SBR does not come with a battery and charger. However, most players prefer purchasing a 7.4v lipo and balance charger separately. Charger and Battery Not Included