Shimano sets the benchmark with the next generation of mountain bike shifting m9000 xtr rapidfires with vivid indexing are there slickest shifters yet light to the touch but positive and crisp vivid indexing provides a constant amount of shift lever force across all sprockets instant release for super fast shifts delivering the chain to the next gear the moment the lever is actuated with no hesitation 2 way release allows the upper shift lever to activated by either your thumb or index finger