Application: it helps to install the wear sleeve and seal of the Front crankshaft more easily without damaging the seal and leakage. Make sure that the installation depth of crankshaft oil seal is correct.With this newly revised tool the 303-1509-01 isn't required. Only use the supplied adapter ring on 2011-2019 models (BC3Z-6700-A seal). DON'T use the adapter ring when working on a 2020 and newer models (LC3Z-6700-A seal).