Moser Engineering performance aluminum differential covers are made of 356 T6 aluminum and are designed to improve ring and pinion gear life, as well as the appearance of your vehicle. They are a support-style cover that stiffens up the main cap area, helping your gears to last longer and even further reduce the amount of ring deflection. The covers weigh only 6 lbs. And include All necessary bolts, washers, and gaskets.