E Thirteen Helix 12 Speed Cassette ClusterBuilt for the demands of modern mountain biking, this model offers a highly durable and dependable build for tackling every obstacle that the trail throws at you. It's in e.thirteen's DNA to solve problems and that's why they created the Helix R 12 speed cassette cluster. It's available in several different finish options which feature a tough aluminium construction, as well as a nickel finish option that's exclusively made of steel.Future-Proof Your Bike with e*thirteen HelixThe Helix R 12 Speed Cassette is an upgrade to any SRAM Eagle or Shimano 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.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. As an added bonus, Helix R 12 speed clusters are backward compatible with and can be used to upgrade your existing TRS+ 9-50 cassette.When installing the Helix R cassette, as with any cassette, e.thirteen recommends checking chain wear. If your chain shows 0.5% or more wear, you will significantly decrease the wear life of your new cassette. Installing a new chain with your new cluster is a much better and economical solution.The Intergalactic 42-50t cluster features PVD finishing that is twice as durable as anodised models.Please note: This product is a replacement cassette cluster and is available in different sizes. Please choose from the menu the option that matches your drivetrain.Features: Cluster Material: Aluminium (Except Nickel option which is Steel) Use: MTB Speed: 12 speed Ratio: Multiple options available to selectTechnologies: Compatibility: The Helix R 12-Speed Cassettes work flawlessly with Shimano and SRAM 12 speed drivetrains, despite the challenges in designing for the different cog spacing and chain behaviour. Performance: The improved performance of the Helix cassette features great Shimano 12 speed shifting performance and improved reliability of steel and aluminum assembly. The Intergalactic PVD finishing is twice as durable as anodised models. And it is 60g lighter. Cost Savings: The aluminium one-piece 42/50 tooth cluster is easily replaceable so riders can keep their steel cluster for multiple seasons and freshen up as needed without buying a whole new cassette. More Range: 556% more range. Durable and Serviceable: Helix R features replaceable gear clusters and intergalactic PVD finishing. Low Weight: Lighter than both XTR and XX1.Buy E Thirteen Components from Chain Reaction Cycles, the World's Largest Online Bike Store.