The Bilstein B4 Series 44-400156 is a premium OE replacement air strut specifically engineered for the front left position of the Mercedes-Benz S-Class (W223). Designed to restore the vehicle's original ride comfort, handling, and safety, this monotube strut integrates seamlessly with the factory electronic air suspension system. It provides constant damping power under any load and maintains strict OEM standards for durability and fitment. Components included in this unit: - Air Suspension Strut (1 pc): 44-400156 - Integrated Air Spring - Electronic Damping Valve