Shimano Altus M310 7/8 Speed Rear Derallieur The Shimano Altus rear derailleur features an advanced light-action, long-cage design with Teflon-coated bushings. What sets the Shimano Altus derailleur apart from other rear derailleurs is its unique 13 tooth upper and 15 tooth lower pulleys that provide a 43 teeth chain wrap capacity (more than conventional 11 tooth pulleys) and enable them to rotate with less friction. Features: Advanced light-action design Teflon-coated bushings Direct-attach rear derailleurs Specifications: Cage Length: Long Cassette Spacing: Shimano/SRAM 8 Chain Wrap Capacity (teeth): 43 teeth Speed: 7/8-Speed Pulley: 13t upper & 15t lower Largest Cog (teeth): 34 teeth Shifter/Derailleur Compatibility: Shimano Weight (g): 326 g | Shimano | Altus Rd-M310 7/8 Speed Rear Derailleur | Black | Long Cage, 7/8 Speed