The Bilstein B4 series is a premium gas-pressure shock absorber designed to restore the original performance and handling characteristics of your vehicle. This twin-tube shock absorber is engineered to meet or exceed OEM standards, ensuring a perfect fit and reliable operation. This item is sold as a single shock absorber. For a complete rear axle restoration, it is recommended to purchase this item in a pair (2 units) along with the following mounting hardware (not included): Polyurethane Bump Stop, Dust Cover/Protection Boot, and Upper Shock Mount (part numbers: 33521137972, 33521092362). Features: OE quality, constant damping power under any load, high traction and precise handling.