RCV Performance Ultimate CV Axles simply replace your Jeep JK's weak Dana 44 U-joint axle shafts with a high-strength constant velocity design. Tests prove Ultimate CV Axles to be twice as strong as OEM Jeep JK shafts, and they're just as tough at a straight angle as they are at extreme angles - where U-joints are weakest. Ultimate CV Axles also eliminate U-joint binding to allow smooth transfer power to the ground.