Exotek TLR 22X-4 HD Aluminum Gear Differential Case. This CNC machined 7075 aluminum differential case is an excellent upgrade to the TLR 22X-4 platform. Offering increased durability and precision over the stock components this differential case helps keep you on the track longer without worrying about drivetrain issues. Additionally the aluminum construction helps to transfer heat resulting in more consistent differential action throughout your run. This case weighs in at 8 grams and can be used in the front, center or rear differential. Package includes one TLR 22X-4 HD aluminum gear differential case and five shims.