The shimano saint m820 10 speed i spec b right hand shifter with versatile positioning ability is optimised for 1 finger braking with crisp instant shifts the multi release allows multiple gear changes from both levers with one sweep further adding to the speed of shift adding to this the 2 way release where 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 the saint m8320 is to be used i