Shocks typically come in three different forms: mono-tube high pressure gas shocks, twin-tube low pressure gas shocks, and twin-tube hydraulic shocks. All modern automotive shocks are filled with fluid, and as their piston moves through that fluid, they will produce increasing amounts of foam (cavitation) as the piston speed increases. Pressurized gas is added to modern shocks to delay the foaming. It keeps the gas apart from the fluid, which keeps performance levels up for longer.
And that means a decent ride and great handling, regardless of the driving condition.
Tire Rack stocks a number of gas shocks from the following brands: