This differential cover has an increased oil capacity of approximately 1/2 quart more over stock for better performance over a longer duration. Built in internal and external fins transfer heat from the oil to the outside air for greater cooling capabilities. This cover incorporates a magnetic drain plug to capture loose particles for improved protection. Included calibration plug is located at a specific height preventing any overfilling and taking the guess work out of servicing your axle. Optional PRO Series deep-reach magnetic fill plug (PN: 46-00003) is a great addition to combine with this cover. All necessary mounting hardware is included. Reuses factory gasket.