The QA1 GM Coil-Over Shock is a great option for anyone looking for fully adjustable ride height and valving control. Choose a from double, single, Drag "R" Series or non-adjustable valving to fit your driving style and you are on your way. Adjustable Coil-Over Shock Features: Available in independent compression and rebound double adjustable, simultaneous compression and rebound adjustable, or drag "R" Series adjustable, Lightweight Billet Aluminum Coil-Over Shocks, Made in the USA, Easy, Bolt-In Installation, Ride Height Adjustable, 100% Dyno Tested and Serialized, Serviceable and Rebuildable by QA1 Authorized Service Centers, Made in the USA, Non-Adjustable Coil-Over Shock Features: Steel, Stock Appearing Shocks, Easy, Bolt-In Installation, Coil-Over, Ride Height Adjustable,