Bingo Airsoftworks shows us how to install this kit for P90... "Now available, Bingo Airsoftworks Wolverine Airsoft SMP P90 Drop In Kit. This is a direct replacement for the P90 AEG gearbox. The only modification needed to the P90 is a hole drilled for the air line to exit. Installation is extremely simple. Just slide out the stock gearbox and then slide in the P90 drop in kit. It was designed so the stock M4 nozzle will work with the P90 hopup; no custom nozzle is needed. The drop in kit is available for $495 (free shipping US)."