Left hand inner 4340 Chrome Moly axle shaft for XJ, YJ & TJ with 30 spline axles, 16.6″. Yukon 4340 Chrome-Moly axles provide up to 50% increased strength over stock axles for use in extreme performance applications with large tires and high horsepower. Yukon’s 4340 axles are manufactured using the latest technologies and the highest quality materials to ensure high strength and long life. Limited Lifetime warranty covers manufacturing defects and axle breakage for as long as you own the vehicle. This warranty is not transferable to another party. “No Questions Asked” replacement for first warranty return, however Yukon reserves the right to either replace axle or refund original purchase price after the first warranty claim. Yukon (through Randy’s ring & pinion) makes final determination on warranty considerations.