Light, positive & crisp to shift, the Vivid indexing system delivers a constant amount of shift lever force across all 10 sprockets, guaranteeing smooth shifting anywhere on the cassette, anywhere on the mountain. Equipped with the Shimano 2-way release trigger engagement, which allows shifting from various riding positions; 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.