Stainless Steel Bearing for Airsoft : 1.Air gun gearbox stainless steel bushing group 2.Essential part for upgrading your Airsoft AEG. 3.To build a tight & durable gearbox. 4.Design for high-speed operation & heavy load prevent cling by burning. 5.Design for 6mm/7mm/8mm Gearbox Version. 6.Suitable for ALL AEG brand with appropriate gearbox.