Here I have my upgraded king arms V2 gearbox. The upgraded include the cylinder, cylinder head, piston, piston head, spring, nozzle, and spring guide. It shoots about 20 RPS and 370 FPS with a stock motor and standard 9.6 volt battery. It runs as it is but it might need a new set of trigger contacts. Price negotiable hit me up with offer. Would tra de for a dye i4 and you ship first. Thanks for reading!