This bearing bushing set can be utilized with 9mm, 10mm, 11mm, & 13mm Diameter Guide Roller Ball Bearings. As the bushing is threaded itself, it creates the screw stronger much less prone to flex. Also, thanks to the improved energy, the roller angle can also be less likely to want to alter even yet in the big event of a big crash. Additionally, in the event that nut that secures the roller comes down, the bushing will not quickly come loose. Threaded Bearing Bushing x4 Wrench x1 Thread means roller will remain attached much longer if its attaching nut happens in the future off. Appropriate for rollers: products 15344, 15345, 15475.