The Shimano Deore M6100 12-speed Upgrade Kit includes everything needed to enhance your drivetrain. The RD-M6100 Rear Derailleur ensures smooth, efficient shifting and supports cassettes up to 51 teeth. The cassettes are designed with Rider Tuned gear steps for optimal cadence control on diverse mountain bike terrain. Featuring RapidFire Plus technology, the shift lever allows for rapid shifting, enabling you to downshift up to three gears with a single stroke. Additionally, the M6100 chain delivers dependable shifting performance. Deore M6100 Upgrade Kit Includes Shimano CS-M6100 Cassette Cassette Cogs: 10-51t: 10-12-14-16-18-21-24-28-33-39-45-51t Finish: Anodized Compatible Freehub: Shimano Microspline Shimano RD-M6100 Rear Derailleur Cage Length: SGS/Long Max Low Sprocket: 51t Pulley size: 13t Shimano SL-M6100 Shift Lever Mount: 22.2mm clamp or I-Spec EV Max multiple shifts: 3 Shifter type: Rapidfire Plus Included Derailleur Cable: Optislick Shimano CN-M6100 Chain Number of links: 126 Quick link included (SM-CN910-12) Shimano Deore Ecosystem and compatability