The shimano slx sl m670 10 speed 2nd gen rapidfire shifter at ough aggressive and light weight dyna sys 10 speed slx rapidfire shift levers with vivid indexing and 2 way release function light to the touch but positive and crisp vivid indexing provides a constant amount of shift lever force across all 10 sprockets shimano slx sl m670 10 speed 2nd gen rapidfire shifter features 2 way release allows shifting from various riding positions the upper lever still performs the same shift fu