base is an elite force m4 with the micro switch gearbox. has been radiused and polished to increase strength and efficiency. aoe has been corrected and the gears are shimmed. shoots 25-30rps depending on how good your battery is. fps is 320, perfect for cqb. It's completely lipo ready. parts list: 18:1 gears, krytac 30k, gate asr, m120, Eagle force Arl, krytac hop up, polished steel cylinder, jg 3/4th metal tooth piston, aluminum o-ring nozzle, ball bearing spring guide