The JK Axle Sleeve and Gusset kit is designed to reinforce the weak axle tubing and knuckles on JK Dana 30 or 44 factory axles. The sleeves are designed to slide inside the factory tubes and provide increased durability and support throughout the axle. This prevents unwanted bending or breaking under extreme conditions. The knuckle gussets fit the profile of the upper portion of the knuckles and works to strengthen them in the weakest areas. Tested in the demanding terrain of the Baja race coarse in Mexico on our Jeep Speed Wrangler with hundreds of miles of punishing abuse.