The Guarder Steel Double Oil Channel Bushings are designed with two grooves cut into the center of the bushing, so that oil collects in these grooves and is constantly interfacing with the surface of the gear axle.

Steel bushings are recommended as the first step in any upgrade - some AEGs come with plastic or cheap pot-metal bushings, which may crack, melt, or otherwise deform with high-quality gears pulling a heavier load.