For Shimano Altus SL-M310 3/8 3X8 Speed Trigger Shifter Dual Lever Shifters L+ R
Right shifter is a trigger-type 8 speed shifter, with one lever for down-shifts and a thumb button for up-shifts. Type: 1 pair(Left +Right Shifter). Left shifter is a friction / ratcheting thumb lever for triple cranksets.