The Action Army 6.01mm AEG Barrel 590mm. Fits inside AEGs that require this length. This is a 6.01 inner barrel diameter is very precise. A very popular choice as an alternative to the Prometheus. One piece high grade metal machined. Precision smooth inner bore with nickel plating. This inner barrel is an upgrade to improve your replica’s performance, accuracy, FPS, and range compared to stock replica barrels.