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.