The Park Tool E-Bike lockring tool is designed and built to remove and install the lockring that retains front chainrings found on Shimano STEPS e-bike motors. Features: Fits Shimano(R) STEPS(R) E6100, E7000, E8000 and E9000 e-bike motor systems For lockrings with 54mm outside diameter and 16 notches Replacement for Shimano TL-FC39 tool 36mm hex drive to be used with Park Tool TWB-36 Crow Foot and a torque wrench to properly measure torque Constructed of 4140 heat treated steel and plated for long life