The King Arms 8MM Reinforce Gearbox for AK is the best way to upgrade your gearbox if you are shooting high fps, 450+. The purpose of the 8mm ball bearings is to reduce the friction put on the gears fulcrum while spinning. Don't make the mistake of thinking the only way your gears can break is at the teeth. High power springs with mediocre bushings or bearings can break the gears at the stem. A break at the stem is potentially more dangerous to the gearbox than just a few teeth breaking off. The King Arms 8mm Reinforced Gearbox is designed to prevent damage to the gears and to prevent gearbox failure due to high stress. If you like your high powered gun performing in tip top condition you need this reinforced gearbox.
Manufacturer: King Arms
Material: Reinforced Zinc Alloy
Design: Version 3 AK AEG
One (1) Gearbox Shell, One (1) Selector Plate, Six (6) Bearings