The Bilstein B3 Rear Air Suspension Spring (40-221595) is a premium OE-replacement component designed specifically for BMW X5 (E70) and X6 (E71/E72) models equipped with self-leveling suspension. Engineered to restore the vehicle's original ride height, comfort, and load-carrying capacity, this air spring ensures optimal safety and stability. Unlike universal alternatives, Bilstein B3 air springs are manufactured to strict OEM quality standards. Features: High-quality rubber and mounting components, resistant to aging and extreme temperatures. Package include: 1x Air Suspension Spring (Rear). Compatible with both Left and Right sides. Professional installation is recommended to ensure correct calibration of the self-leveling system.