Revolution Gear and Axle Discovery Series D44, 4340 Chromoly Front Axle Kit, 30 spline kit ONLY works with factory locker. Kit comes with 2 inner axles, 2 outer stub axles, 2 Dana Spicer 5-7166X U-joints and 8 Full Circle Snap rings to hold it all together. Revolution uses the large1350 style u-joint. Using the substantially larger 1350 u-join provides a substantial strength increase. All Discovery Axles are backed by a 10 year warranty against failures, including but not limited to U-Joint failure.