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 Gas-a-Just is available as an OE monotube replacement and as an OE twin-tube performance upgrade. The KYB Gas-a-Just has two separate working chambers: An air-free hydraulic piston and valve area for responsiveness & 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. With a faster response and up to 25% more damping over OE twin-tube designs, KYB Gas-a-Just shocks are a great way to give your vehicle additional handling and control capabilities. Larger, aftermarket wheels can add up to 25 pounds of additional weight to each corner. KYB's shock valves are designed to help restore steering response to what the vehicle manufacturer intended.