Manufactured by Teraflex. The TeraFlex JK/JKU Axle Sleeve & Front Upper Knuckle Gusset Kit is designed to reinforce the weak axle tubing and knuckles on JK/JKU Dana 30 or 44 factory axles. This prevents unwanted bending or breaking under extreme conditions. INCLUDES: � Short side inner axle sleeve & long side inner axle sleeve (# 4990700) � Front upper inner knuckle gussets pair (# 4990800) NOTE: � Does not fit Rubicon Recon w/ Dana 44 front axle w/ 3/8� wall. INSTALL TIME: 5 Hours (Complete Kit)