Chainring lockring tool from Park Tool. Precisely machined for a perfect fit, the LRT-1.2 removes and installs the front chainring lockrings found on DJIA(R) Avinox & BoschA(R) Gen 2 e-bike motors once the crank arm is removed. Integrated 3/8" drive fitting allows compatibility with most ratchet handles and torque wrenches for tightening to proper torque specifications, and the heat-treated and plated 4140 steel construction ensures durability and long life.