There are three different types of shock absorbers. With the twin-tube damper, the piston pushes hydraulic fluid into the balance chamber of an outer tube. When the gas pressure twin-tube dampers are finer, there is (instead of air) a gas cushion above the oil levels of the balance chamber. By contrast, the "floating" piston separates oil and gas chambers with a gas pressure monotube damper.
The right functioning of the shock absorber ensures proper handling, shortens the braking distance, prevents premature tyre wear and is responsible for optimum traction.