JBU is known in the airsoft industry for their high end quality manufactured airsoft AEG internal upgrades and accessories. JBU manufactures a wide array of airsoft internal upgrades, such as high speed and high torque gears, ball bearing bushings, ball bearing spring guides, bearing piston heads, full metal pistons, springs, pinion gears, and most notably precision machined tight-bore inner barrels. All of JBU’s products are made from premium grade materials and are precision machined, to meet strict tolerances. For high end and high quality airsoft internal components and upgrades, JBU is one of your best options. Airsoft Megastore carries a large selection of premium JBU internal upgrades for the LOWEST price on the market!