TJ 4.5 Inch Extreme-Duty Long Arm Suspension Lift Kit. Rubicon Express was the first to comercially offer a long arm suspension system for the Jeep TJ. Our Extreme-Duty Long Arm system set the industry standard by which all other kits have been measured. It is designed to be a complete suspension replacement, which utilizes longer control arms to improve lifted suspesnion geometry. This system will offer you superior stability on and off road, reduced torque roll, and enhanced trail traction over standard short arm lift systems. The Rubicon Extreme-Duty Long Arm suspension system includes a three-piece belly pan for easy transfer case and transmission access. Our TJ Extreme-Duty Long Arm suspension System is the best performing and most technologically advanced system of its kind; there is no better long arm suspension system available for your TJ. The first and still the best.