The Shimano SL-M8100-R Deore XT Shifter is arapidfire Plus 12-speed right hand shifter with Instant, Multi and 2-Way release to exceed the demands of ever changing bicycle designs and riding styles.Light to the touch but positive and crisp, Vivid indexing provides a constant amount of shift lever force across all 12 sprockets.2-Way release: the upper lever still performs the same shift function, but it can now swing in either direction allowing it to be released by the thumb or index finger. Shimano SL-M8100-R Deore XT Shifter Features Multi Release allows multiple gear changes with one sweep, further adding to the speed of shift Multi-bearing design uses two ball bearing units to provide a low-friction and reliable shifting action One piece lower alloy thumb release lever with anti-slip increases durability and gives sharp precise shifts For use with 12-speed transmissions only Raised optical gear display instantly shows you what gear you're in and allows clearance for suspension lock out clamps below Multi-position adjustable handlebar clamp for custom lever positioning