This category includes gearbox upgrade parts and spare parts for airsoft guns, designed for maintaining, repairing, or upgrading the internal mechanism of AEG replicas. The gearbox is the core mechanical unit of an electric airsoft gun, containing components such as gears, piston, cylinder, and spring that drive the firing cycle.

The selection includes components such as gear sets, pistons, piston heads, cylinders, cylinder heads, springs, spring guides, tappet plates, bushings, bearings, and other gearbox internals used to maintain or tune an airsoft replica.

Replacing internal components can help increase durability, change rate of fire, adjust power output, or improve air seal, which can enhance the reliability and performance of an airsoft gun.

This category includes a wide range of gearbox spare parts and upgrade components compatible with various airsoft gearbox versions and platforms.