Sram x01 dh type 21 7 speed rear mechthanks to its horizontal parallelogram design x horizon can keep the chain gap the same across all 11 gears by taking vertical movement out of the equation this design doesnt just make shifting fasterit reduces shift force and eliminates ghost shifting x horizon architecture provides more responsive shiftingx actuation with more cable pull provides better system performance and durabilityx horizon eliminates ghost shifting very commonly found on dh b