This JG Silent Bore Up Piston Head can only be used in conjunction with a Bore Up Cylinder and Bore Up Cylinder Head. * Disclaimer: Any and all Airsoft upgrade parts purchased from Airsoft Megastore will be used/installed at owner"s discretion. Actual performance results depend on quality of installation, Airsoft AEG barrel length, tightness of the air nozzle seal, and other possible performance-affecting factors. We are not responsible for any damage that may occur with improper installation. For best results, please do all upgrades at a certified professional Airsoft technician/shop.