evo.com | Shimano Rear Derailluers > Giving that old commuter or hardtail mountain bike a refresh? The Shimano Altus RD-M2000 9-Speed Rear Derailleur will blow your mind with how well it shifts. It's a testament to Shimano that they continue to improve every one of their products, even if that product's not at the sharp end of development. Your 9-speed cassette has never shifted this well! New Shadow Design with Optimized Slant Angle Lowers shift effort while improving shifting and driving stability. Smallest Cog 11T Stronger Return Spring for Crisp Shift Feeling Rear Derailleur / Shifter Compatibility All Shimano 9-Speed HG Cassettes, 9-Speed Mountain Shifters, and 9-Speed Chains. Largest Cog 36T | Shimano Altus RD-M2000 9-Speed Rear Derailleur 2021 - SGS/Long Cage