The most common internal shock absorber designs are monotube and twin tube.
The biggest distinguishing feature between the two styles is that in a monotube, the piston rides directly on the inside wall of the shock body. In a twin tube, the piston rides inside a compression tube which is spaced slightly in from the wall of the shock body.
Twin tube shocks are cost-effective and provide satisfactory safety, handling, and control for most driving conditions. A monotube design offers what most drivers consider to be superior handling and performance, as well as a ‘sporty’ ride. Because of these performance characteristics, monotube shocks often are original equipment on luxury cars and SUVs, and are common aftermarket upgrades on vehicles originally equipped with the twin tube design.
Unless pricing is most important in a repair or upgrade discussion, many automotive experts and driving enthusiasts consider monotube shocks are preferable because of superior:
-- Ride quality,
-- Durability, and
-- Ease of installation.