The suspension in your trailer is just as important as that of your car; without proper suspension your trailer will have a rougher ride down the roadway and any cargo aboard could be damaged before reaching your final destination. A torsion bar is crucial to offer proper elasticity and durability, and all the required parts need to be functioning properly to keep the suspension in working order. This Left Hand Torsion Arm 3.7K Assembly Vault is a complete setup for replacing the arm of your torsion bar. Coated with a zinc-rich finish, the left handed torsion arm is better protected from erosion and rust whenever you encounter water. It is crucial to replace the arm of your torsion bar when required; while one side is attached firmly to the chassis, the other end is attached to the suspension arm, and all parts work together to keep your suspension intact. For this left hand arm, the replacement will fit to the drivers side of the trailer. The vault portion of this kit is a Hybrid Lubrication System offering the best wheel bearing lubrication and protection. All necessary hardware for a proper replacement is included with this kit.