The e*thirteen Helix R 11 Cassette Cluster is a sweet upgrade to any SRAM or Shimano 11-speed drivetrain. Not only is it lighter than the flagship XTR and XX1 cassettes, but you'll also enjoy a considerably wider gear range thanks to the smaller 9-tooth cog. This gives you the option to step down one chainring size to get better low-end gearing on climbs, all while maintaining the same top-end gearing so you don't spin out on the descents. The Helix R works efficiently with both Shimano and SRAM 11-speed drivetrains, and the aluminum 46t cog is easily replaceable—allowing you to freshen up the granny gear without having to buy a whole new cassette.