Nitro (NPCOVER-AAM11.5) Black Aluminum Finned Differential Cover for GM/Dodge 11.5" Differential Finned aluminum dissipates heat faster than steel reducing the operating temperature inside the differential extending the life of the components Recessed bolts eliminate the potential for bolt sheering when crawling over rough terrain Aluminum can't rust and a Nitro aluminum differential cover will keep the undercarriage looking great all year round Nitro's wide selection of available covers makes it possible to equip both the front and rear differentials with Nitro covers on many vehicles Made in the USA