This set comes with 2 front and 2 rear RS5000x Series shocks. Developed by the ride engineers at Rancho, this unique and exclusive rebound valving system and advanced compression phase of the shock absorber is at the heart of the RS5000X. Cross Tuned technology featuring exclusive rebound valving system and advanced compression phase improves overall handling and performance. Exclusive Progressive Engagement Valving is custom-tuned for each vehicle to help reduce initial impacts at low speeds and minimizes a rough ride. The RS5000x series features a 16mm nitro-carburized piston rod to resist scuffs & corrosion, double-welded loops at stress areas, 35mm sintered iron piston for enhanced structural integrity and polyvinyl protective boot. Large twin-tube body filled with all-weather fluid allows for cooler operation, increased vehicle control and ability to withstand internal temperatures of -40 to 248°F. Polyurethane rebound bumper and rubber bushings help absorb ride harshness while the fluon-banded piston enhances responsiveness to changing road conditions for an overall smoother ride. Nitrogen gas pressurized to 150 PSI to minimize air-to-oil mixture to reduce damping performance fade and foaming. The compression control valve is custom-tuned for each vehicle to regulate fluid transfer to absorb impacts without disc flutter and help maintain shock motion control. The low-friction, self-lubricating seal retains gas and oil for quicker rebound and smoother compression while the application-specific piston delivers heightened control of shock motion due to the expanded piston area. Buy with confidence, the RS5000x series shocks come with Rancho's limited lifetime warranty. This set is compatible with 2005-2016 F250 Super Duty and 2005-2016 F350 Super Duty dual rear wheel (Standard/Extended/Crew) cab vehicles. Models must be 4WD with 0" Lift.