The Sorbo Pad Sorbothane Cylinder Head Damper from SorboPads.com is specifically designed for the version 7 AEG cylinder head. It may also work on other cylinder heads with centered nozzles and standard diameter cylinders. It is composed of 70-H durometer Sorbothane (semi-soft polyurethane) which is designed to be compressed over 1 million times before needing replacement. If you want to prevent cracked gearbox shells, reduce piston stroke noise, and improve sector gear angle of engagement, then this is a must have for any airsoft mechanic.
Clean cylinder head with soap and water. Dry thoroughly with paper towel. Apply CA glue (super glue, crazy glue, etc.) to cylinder head. Carefully center damper against the cylinder head and press them together. The two should bond very quickly, but you should wait 10 - 15 minutes before installing cylinder head back into the gear box. Make sure no glue gets onto the cylinder head o-rings.