The KYB Gas-a-just monotube shock absorber has additional performance advantages over the traditional twin-tube design: It can instantly, automatically adjust to your performance needs and never experiences fade due to aeration. The KYB Gas-a-just has two separate working chambers: An air-free hydraulic piston and valve area for responsiveness and control, and a second high-pressure nitrogen gas area with a floating piston that provides a comfortable ride during normal driving and adds instant performance on demand. Adds up to 25% more damping performance over original equipment shocks Components and valving designed specifically for Ford F-150s Gas-a-Just monotubes include additional damping over OE design for vehicles that work, tow, and have larger, heavier tires & wheels High pressure monotube design separates the gas and oil for fade free operation and instant response Fluid leaking can be a cause of shock failure, the KYB Gas-a-just has an ultra-smooth triple chrome plated chrome piston rod to reduce seal wear The higher gas pressure of the KYB Gas-a-Just responds quickly to improve steering response Electronic safety systems depend on the suspension, brakes and tires operating as the vehicle manufacturer intended. The KYB Gas-a-just helps keep Electronic Safety Systems performing as designed. Package Dimensions: 22.835 x 2.559 x 2.559 inches Package Weight: 5.06 lb Package Quantity: 1 UPC: 781552013570 B-stop: N Compressed Length: 16.77 Dust Cover Included: Y Extended Length: 27 Country of Origin: JP