The Prometheus Shim set for AEGs include 6x 0.1 mm, 6x 0.2 mm and 6x 0.3 mm, 6x 0,5 mm shims. Shims are one of the smallest pieces in the gearbox, but they are also the most important. Shims are responsible for spacing the gears properly to avoid uneven and premature wear. An improperly shimmed gearbox is doomed for failure. In order to shim a gearbox precisely you need precision shims, and Prometheus has just that. These steel shims are precision cut for exact spacing.