RCV Performance Ultimate CV Axles simply replace your Jeep JKs 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. We have gone a step further by upgrading the inner shafts to 300M, which provides an even greater tolerance to stress. Ultimate CV Axles also eliminate U-joint binding to allow smooth transfer power to the ground. Even if you have big tires and big power there are no worries. Ultimate CV Axles are low maintenance and operate with a smoothness you can feel - whether off road or on the street. And we back it all with a "No Questions Asked" limited lifetime warranty.