As you'd expect from Shimano's top-tier mountain bike group, the XTR SL-M9100 Trigger Shifters are precise, quick, and offer an ergonomic design that's comfortable to keep a finger on for fast changes on steep climbs and rooty descents alike. In years past we expected to see a lot of similarities between a shifter and its predecessor, but this year Shimano broke the mold with an all-new shifter that features a sleek, dark look, and faster, easier actuation. The new shifter reduces lever access time bu a claimed 20%, while simultaneously reducing the force required to operate by 35% compared to the M9000. The lighter force makes it easier to rapidly shift through your cassette during transitions from steep descents to punchy climbs, so you can land at the perfect gear, and avoid shifting under serious load. The new shifter is available with Shimano's I-Spec EV which allows you to better customize your cockpit. I-Spec EV features 60-degrees of rotational adjustment, compared to the 15-degrees of I-Spec II, and 14-millimeters of side-to-side adjustment to achieve comfort and control on the bars. Clamp-mount shifters are also available for riders with smaller hands. Should you be opting for a two-by setup, Shimano offers a single-blade left lever that simplifies front shifting by allowing you to push with your thumb to shift up to your big ring, and push a second time to release back to the small ring. The Shimano SL-M9100 Trigger Shifters are available in left or right hand units. The right lever is compatible with 12-speed Shimano R9100 groupsets; the left lever is, with Shimano's double R9100 cranksets. Left and right are sold separately, so be sure to order one of each if you're looking to run a double setup.