Gas-a-Just™ Front Driver or Passenger Side Monotube Shock Absorber (KG5499) by KYB®. Quantity: 1 per Pack. 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.