The HELIX R 12 Speed Cassette is an upgrade to any SRAM Eagle™ drivetrain, with more range than any other cassette on the market. The 9 tooth cog lets you step down one chainring size while keeping the same top end gearing and provides not only better ground clearance, but an overall lighter drivetrain. The aluminium one-piece 42/50 tooth cluster is easily replaceable so riders can keep their steel cluster for multiple seasons and freshen up granny as needed without buying a whole new cassette.It’s in our DNA to solve problems. Helix components are engineered to bridge the compatibility gap between SRAM™ and Shimano™ components, ensuring versatility and flawless performance. Future-proof your bike with e*thirteen Helix.Works flawlessly with Shimano™ and SRAM™ 12s drivetrains despite the challenges in designing for the different cog spacing and chain behavior. Additionally, if your wheel has a SRAM™ XD™ Driver and you want to upgrade to Shimano™ 12s, you not only save money on the cassette, you don’t have to spend the extra on a new hub driver either.Unlike SRAM Eagle™, Helix R cassettes have replaceable gear clusters. That means ongoing service and replacement costs will be less than half that of SRAM™ cassettes. Key Features: 556% More range than any other cassette on the market, 42,50,Weight*: 345g,Compatible with SRAM and Shimano 12speed drivetrains,Improved shifting performance including Shimano™ 12 speed compatibility,Improved interface between steel and aluminium clusters,.