The Mercedes Back Shock 166 with Wire Star (Part No. 166 320 01 30) is a rear air suspension shock absorber designed for Mercedes-Benz SUVs built on the W166 platform, such as the ML-Class (2012–2015) and GLE-Class (2015–2019). The term "with wire" refers to the integrated electronic connection used for active suspension control, allowing the vehicle's onboard systems to continuously adjust the shock's damping characteristics based on driving conditions. This shock absorber is part of the AIRMATIC air suspension system, combining pneumatic support (air spring) with electronically adjustable dampers to provide a smooth, adaptive ride. The "Star" indicates it meets Mercedes-Benz OEM standards, ensuring compatibility and performance.

Functionally, this component plays a critical role in ensuring ride comfort, handling stability, and load-leveling in Mercedes-Benz SUVs. As part of the rear suspension, the shock absorber dampens road vibrations and controls rebound when driving over bumps or uneven surfaces. The electronic connection allows the system to adapt in real-time — softening the ride during normal driving for comfort, and stiffening it during cornering or braking to enhance stability and control. It also works with the vehicle’s self-leveling feature to maintain consistent ride height regardless of cargo or passenger load. This makes the 166 320 01 30 rear shock absorber essential for both driving performance and passenger comfort in luxury SUV models.