ETU for 3 and 5 round burst Pre-installed MOSFET 6 Position Retractable Crane Stock Polymer Receiver Full M-LOK Metal Rail Fully Licensed by Knight's Armament Material Polymer / Aluminum / Metal Motor Standard Motor25000rpm Gear box bearing 8mm ball bearing Inner Barrel Length 245mm Magazine 90 Rounds Overall Length 674.9mm Weight 2760g Electronic Trigger Yes MOSFET Yes   Battery & Charger not included