(All Kits include the YJ Disconnect Block Off Kit)Front 4340 Chrome-Moly axle kit for Dana Spicer 30 ('84-'90 XJ, '97 and newer TJ, '87 and newer Wrangler) with 27 splines. 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. 4340 axles are manufactured using the latest technologies and the highest quality materials to ensure high strength and long life. This kit comes with inner & outer axles for both left and right sides along with Dana Spicer U/Joint. Limited Lifetime warranty covers manufacturing defects and axle breakage for as long as you own the vehicle.