Kcnc Bicycle Lightweight Bearing Built-in Derailleur Parts Jockey Wheel 13T Pulley 11S/10S/9S Black 304387

9/10/11 quick useMaterial CNC machined 7075 aluminum alloyBearings stainless steelFits SHIMANO, CAMPAGNOLO, SRAM 9/10/11 speed derailleurs (not compatible with SRAM guide pulleys.Smooth rotation with ball bearings.It is more rigid than resin pulleys and does not lose power.Ideal for upgrading bushing derailleurs on mid-range derailleurs.Can be used for both guide pulley (upper) and tension pulley (lower).For the number of teeth, we recommend the size that comes standard with the derailleur.1 pieceAfter installation, be sure to check the operation of the gear shift on the adjustment table before riding. If the derailleur hanger is bent, the chain may come off and damage the frame or rear derailleur.