Extremely high pressure spring for extreme upgrades. Offers over 400 fps of power on PSG-1. Actual results depend on barrel length, workmanship, air nozzle seal, and many other factors.
Please check AEG Spring Comparison Chart from
http://www.airsoftcanada.com
Disclaimer: All aftermarket upgrade parts require necessary skill or modification to install and assemble, please consult with your airsoft technician if needed.