The bosch lockring tool do lockring assembly activeperformance the tool is used to loosen and tighten the locking ring in the chainring mounting bosch lockring tool do lockring assembly activeperformance features the bosch locking tool for active and performance line ebike is used to loosen and tighten the locking ring in the chainring mounting original bosch tool in workshop quality and therefore 100 accurately for the professional repair this locking tool is req