The Gas-a-just monotube shock absorber is available as an OE monotube replacement for the Edge Sport and Nautilus, while it?s available as an upgrade for the Edge SE, SEL, Titanium. 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.