All NITRO Gears are computer-controlled forgings, forged out of 8620 steel, fully automated turning, single pass cut, and then vacuum heat treated. The sum of these processes is the ultimate aftermarket gear. This is a high-performance quiet gear, perfect for any vehicle from stock and beyond. It will handle the rigors of big tires or high horse power. Fits low pinion applications Not TJ/WJ: Jeep CJ, ZJ pre 96.5. Pre 96.5 ZJ requires ZJ master install Kit, and will be converted from crush sleeve design to solid pinion shim design. Master kit also has required adapter outer pinion bearing.