More Range, Less Weight Engineered for E-bike durability and cross experience compatibility with SRAM™ and Shimano™ drivetrains. This 9-50T combination is the hot set up for your 12 Speed MTB and allows for a 2 tooth smaller front chainring, shorter chain length, more clearance and range with our exclusive 9 tooth smallest cog. Future proof your bike, save weight and cash with the Helix Plus Cassette.  PRODUCT FEATURES Compatible with SRAM™ and Shimano™ 12 speed drivetrains 2-piece design allows for replaceable aluminum cogs E*spec uprated for E-bike use RIDER BENEFITS Reduces un-sprung rear wheel weight for improved suspension function and handling Excellent shifting with Shimano™ and SRAM™ systems without compromise e*thirteen’s wider range and 9 tooth cog allows riders to run a 2 tooth smaller chainring for more clearance and reduced weights Helix R performance at a competitive price *XD™ driver required.   *Hope XD drivers are undersized at the clamp location and require a Cassette Shim Kit click here to get one