Improved Handling and Performance - Cross Tuned technology featuring exclusive rebound valving system and advanced compression phase improves overall handling and performance on and off road Minimizes Rough Ride - Exclusive Progressive Engagement Valving is custom-tuned for each vehicle to help reduce initial impacts at low speeds and minimizes a rough ride Strong and Durable - Features a 16mm nitro-carburized piston rod to reduce scuffs & corrosion, double-welded loops at stress areas, 35mm sintered iron piston for enhanced structural integrity and polyvinyl protective boot Handles Extreme Temperature Changes - 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 Smooth Performance - 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 Dynamic Rebound Spring (DRS) Technology - NEW DRS Technology is a unique internal system that includes a precisely tuned metal spring and fortified interior construction to provide additional control, reduce body roll and prevent rod overextension inside the shock. The Rancho RS5000X series design includes progressive rebound and compression discs. At lower speeds or in the earlier stages of the shock’s travel, an eccentric disc in the valve shim stacks will engage the valving at lower frequencies, helping to control the energy of motion as the cycle of the shock increases or decreases in its action. When hitting a pothole, off-road trail obstacle or similar activity, Rancho’s Progressive Engagement Valving allows for early flow of fluid, helping to reduce harsh initial impacts and to control the flow of fluid in a progressive, gradual manner through the valving. During on or off-road driving activities like washboarding or when travelling a rough fire road, the early flow of fluid helps to minimize a “rough” ride as the piston movement is able to glide through the initial travel motion of the shock with minimal ground impact or force. If needed, the Progressive Engagement Valving will further engage to maintain control and stability.