This is the Level 2 600HP Complete Axle for the 2001-2004 Mustang Cobra (31 Spline Differential). The outer CV is a proprietary material with a unique Carbo Ausse Tempering that gives it a very hard shell and it fits the stock wheel hub. These axles also feature our chromoly 108 mm Porsche-type Ball & Cage inner CV with a bolt-on flange and spline plug to fit the 31 spline differential and our high grade aircraft quality center bars. Designed to handle 600HP at the wheels, it is one solid axle set. These complete axles are a direct bolt-in, just remove the ABS ring from your stock axles and install them on the Level 2 axles. Rated to 600HP with a 1-year warranty. Price listed is for both axles.