aFe Power's new rear differential cover brings performance engineering to the protection of your axle's differential. This differential cover is constructed out of durable sand-cast A356-T6 aluminum with reinforcing ribs for maximum strength. This cover comes with mounting hardware for a hassle-free installation. The differential covers includes an oil level sight glass and deep reach magnetic fill plug for maximum protection. This cover is finished in wrinkle-black powder-coating with machined fins for a distinctive look. 2 Quart Lube Capacity: This cover has about a 2 quart lube capacity at the factory fill level, factory cover holds about 1.5 quarts. Built-in External Fins: Built-in external fins transfer heat from the fluid to the outside air for maximum cooling. Magnetic Drain/Fill Plug: This system incorporates a magnetic drain and fill plug that captures loose particles for maximum rear-end protection. Oil Level Sight Glass: Large oil level sight glass with 1/8'' NPT calibration plug set to the factory fluid level to eliminate overfilling. Group IV synthetic base: This competition proven formulation utilizes a group IV synthetic base along with a proprietary additive package that reduces drag, resist foaming and maintains its viscosity under extreme heat and high loads. Usage: The Pro GUARD D2 Synthetic 75W-90 limited slip gear oil exceeds the performance requirements of API GL-5 recommended for both open and limited slip applications.