DESCRIPTION This bearing bushing set can be used with 9mm, 10mm, 11mm, & 13mm Diameter Guide Roller Ball Bearings. Because the bushing is threaded itself, it makes the screw stronger and less likely to bend. Also, thanks to the improved strength, the roller angle is also less likely to change even in the event of a big crash. Also, if the nut that secures the roller comes off, the bushing will not quickly come loose. • Threaded Bearing Bushing x4 • Wrench x1 • Thread means roller will stay attached longer if its attaching nut happens to come off. • Compatible with rollers: Items 15344, 15345, 15475.