Replace worn rear knuckle cross axis ball joints on the IRS Mustang Cobra with xAxis joints from SPC Performance. SPC's cross axis ball joints feature highly polished electroless nickel plated balls, corrosion and wear resistant moly impregenated nylon races, and dust boots to keep contaminants out & ensure long life. xAxis Joints come pre-greased and are designed to be maintenance free. This kit includes one (1) xAxis joint. Use SPC press adapters part number 29606 and 29610 ot make installation a snap. Don't have a press tool? Use SPC #40940. California Residents WARNING