Derailleur pulleyorigine from Shimano, for derailleur SHIMANO Deore/SLX 12 speeds. The derailleur rollers ensure the tension and the guidance of the chain during the passage of your speeds. The roller and also called "Puley" It ensures the movement of your chain, while the bottom one named "String" its role and that in charge of the tension of the chain. In order to have a good precision and an optimal fluidity, the derailleur rollers must always be in good condition. They will be compatible with the ranges of rear derailleurs SLX M7100, DEORE M6100.Technical characteristics of the roller kit Shimano Deore XT RD-M8100/M8120 12 Speeds:Type of use: RoadCompatible derailleur: RD-M7100-SGS, RD-M7120-SGS, RD-M6100-SGSCompatible range: SLX M7100 DEORE M6100Number of gears: 12Packaging: 2-piece set (top/bottom)Mounting: Rear Derailleur