This bearing bushing set may be used with 9mm, 10mm, 11mm, & 13mm Diameter Guide Roller Ball Bearings. Whilst the bushing is threaded it self, it creates the screw stronger less susceptible to flex. Also, as a result of the improved power, the roller angle can be less likely to alter even yet in the function of a big crash. Also, in the event that nut that secures the roller precipitates, the bushing won't quickly come loose. Threaded Bearing Bushing x4 Wrench x1 Thread means roller will continue to be connected much longer if its attaching nut takes place as time goes by off. Appropriate for rollers: products 15344, 15345, 15475.