Shimano deore m590 9 speed trigger shifterdeore mountain bike rapidfire shifter pods featuring 2 way release for cost effective 9 speed shifting performance features 2 way release 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 mega9 compatible for use with precision 9 speed drivetrain pod design allows the use of these shifters with any brake