A gas spring consists of a cylinder with a piston, where gas in the cylinder is compressed and thus provides a spring effect. A valve in the piston ensures that the movement is damped. For example, a gas spring can be used for a height-adjustable office chair. If you want to adjust the seat height of an office chair, the lower leg length is the determining factor. When adjusting the seat height, the feet must be able to remain flat on the ground and there must be no pressure on the underside of the thigh. Feet, thighs and buttocks must absorb and distribute the body weight. The height of the seat part of the chair also depends on the forward tiltability of the chair.