ASG’s new line of 8mm bearings are perfect for upgrading or repairing your AEG airsoft rifle. They are made from a porous steel and graphite alloy that soaks in oil and grease, reducing the need for re-lubrication. Their solid metal construction can handle a greater degree of stress than ball bearings, so your rifle is less likely to break down. Compatible with any 8mm gearbox. Features: Type: Airsoft AEG internal part, Material: steel and graphite, Diameter: 8 mm