aFe POWER's rear differential cover brings performance engineering to the protection of your truck's rear-end. This differential cover is constructed out of durable die-cast aluminum with reinforced ribs for maximum strength. The Pro Series differential covers include an oil level sight glass and deep reach magnetic dip stick for maximum protection. This cover fits the Ford 9.75 rear axle and is compatible on vehicles equipped with a factory rear track bar. Built-in external fins transfer heat from the fluid to the outside air for maximum cooling. This system incorporates a large magnetic drain and deep reach fill plug to capture loose particles for maximum rear-end protection. Large oil level sight glass with calibration plug set to the factory fluid level to eliminate overfilling.