Nitro (NP1812) Aluminum Heavy Duty Girdle Cover for Dana 60/61 Made from 356 aircraft grade aluminum for durability and strength, then heat treated to T6 specifications and stress relieved Girdle covers are machined using a 3 step CNC process ensuring accuracy and quality, then each cover is inspected, de-burred and assembled by hand and packaged All Girdles incorporate a fill port and a drain port for ease of servicing and on average increase fluid capacity by approximately 1/2 pint, lowering the operating temperature of the differential by 15 degrees The average weight of a Nitro differential Girdle cover is about 7 pounds, larger covers will weigh more Made in the USA