Used to rotate engine flywheel to lock engine at «TDC» to check high pressure fuel pump timing.Used to rotate flywheel on engines with 129-tooth flywheel ring gear and a 29.9 mm (1.18 in.) flywheel housing guide bore diameter. Application: 4024, 4039, 4045, 4239, 4276, 6359, 6619, 6059, 6068, 6076, 6081, 6090, 6105, 6125, 6135, 7400 and 7600 enginesOEM no. ref: JDE81-1 (formerly version of JDG820)High quality aftermarket tool You also can reference our master kit https://www.ebay.com/itm/194893982606