This tool assist you in testing the hydraulic circuit inside the drum and identifying cracks in the drum. Simply place the tool into the drum, use the air nozzle in each marked hole and blow compressed air into the drum to check for leaks. Engineered with a snug fit to an airtight seal for accurate leak detection.Avoid forcing the tool. Manufactured through CNC machining technology to high . After anodic oxidation treatment, it has anti-rust and - properties. Design compatibility test 35R/-4 drum. This tool can effectively detect leaks and cracks, helping you maintain the integrity of the transmission system. name:Reverse Drum Tester Fitment: Only fits for original drums and compatible with 6L80 6L90. (Does not fit aftermarket drums. ) Material: Metal Color: As shown Package Contents: 1 x Reverse Drum Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.