A shock absorber is basically an oil pump, a device used to smooth the push or shake that take place abruptly and roughly and distribute it as kinetic energy. Shock absorbers are crucial in all the motorcycle and automobile suspension, where landing gear is a part of the support systems for industrial machines. A shock absorber is usually a cylinder containing a sliding piston which is cushioned by hydraulic fluid or air.

During 1900's cars use to ride on carriage springs, which are a simple form of spring commonly used for the suspension in wheeled vehicles. With respect to suspension designs, the initial vehicle manufacturers faced early challenges in enhancing driver control and comfort of passenger. These early suspension designs found the front wheels attached to the axle using steering spindles and kingpins, those allowed the wheels to pivot while the axle remained stationary. Other than these, the up and down oscillation of the leaf spring was damped by device called a shock absorber. The initial shock absorbers were simply two arms connected by a bolt with a friction disk between them and were not very durable. Here the resistance was adjusted by tightening or loosening the bolt and their performance was least minded.

Technically, conceptually shock absorbers experienced vast developments over the 20th century. However, the developments in automobiles and the usage of automobiles demanding a new range of shock absorbers at every turn and milestone of automobile industry. Hence, 21st century has been witnessing more sophisticated concepts and designs of automobile shock absorbers.

Several shock absorber designs came into availability in the industry. The adjustable and nonadjustable shocks are basically of two different designs as twin-tube and mono-tube. Whereas, industry focus also turned to customization of the product based on the vehicles they are going to impart with.

•    Basic Twin Tube Design has an inner tube known as the working or pressure tube and an outer tube known as the reserve tube. The outer tube is used to store excess hydraulic fluid.

•    Twin Tube - Gas Charged Design is a major advancement in ride vehicle control technology and also solved many ride control problems that occurs due to an increasing number of vehicles using uni-body construction, shorter wheelbases and increased use of higher tire pressures. Currently, twin tube – gas charged design adapted in original equipment on many domestic passenger car, SUV and light truck applications

•    Twin Tube - PSD Design or Position Sensitive Damping Design is a leap beyond fluid velocity control is an advanced technology that takes into account the position of the valve within the pressure tube. The technology has solved the compromises between soft valving and firm valving. The twin tube - PSD design specialty is that it adjusts more rapidly to changing road and weight conditions than standard shock absorbers

•    Twin Tube -ASD Design or Acceleration Sensitive Damping Design is an answer to the compromises made by ride engineers to bring comfort and control together into one shock absorber. This technology moves beyond traditional velocity sensitive damping to focus and address impact. The intelligence in this technology is that the compression valve will sense a bump in the road and automatically adjust the shock to absorb the coming impact, leaving the shock with greater control when it is needed.

•    Mono-tube design is a high-pressure gas shocks with only one tube that is the pressure tube and does not have a base valve. The difference in actual application is that a mono-tube shock absorber can be mounted upside down or right side up and will work either way reducing the unsprung weight. In addition to its mounting flexibility, mono-tube shocks are a significant component, along with the spring, in supporting vehicle weight.

The 2012 release - Cadillac Escalade came with shock absorbers those decrease the impact of bumps and provides a smoother ride. 5788 from Monroe Sensa-Trac Shock Absorber is applied for 04-06 Cadillac CTS and 5787 from Monroe Sensa-Trac Shock Absorber is applied for 03-03 Cadillac CTS. Monroe Sensa-Trac shocks and struts have been recognized for their trusted ride control product for drivers who want ultimate comfort with added control.

mShock absorbers in 21st century

21st century is known for the innovations in shock absorbers. The shock absorbers and the autos are also structural friendly that the automobile owner him/herself can change or adjust or replace the shocks.
Performance shock absorbers are available in single- and double-adjustable configurations. Double-adjustable shocks have the ability to trim the bump and the rebound separately. Whereas, the single-adjustable shocks allows changes to the rebound portion of the shock. Single-adjustable shocks are more expensive than the traditional or nonadjustable shocks and very less expensive compared to double-adjustables. Few of single-adjustable shocks are the Koni, Competition Engineering, Tokico, and QA1.

Specialty Shocks purpose started with drag racing, because the situation actually requires shocks for the front and rear that are often much softer than stock. While nonadjustable stock replacement shocks do an adequate job of improving handling over worn-out original shocks in the high-performance applications and stock shocks are often found wanting.

Rear shocks are also important in traction equation, and also offer a slightly longer extension to prevent bottoming out the shock when planting the tires, especially with suspensions with an excess of 100% antisquat when there is separation between the tire and the body at launch.

Now the market turned so dynamic that each model of automobile has different set of requirements in shock absorbers. This shows the drastically growing demand for the custom auto shock absorbers products. The basic customization also reflecting in the titles of the products, and few models of adjustable shock absorbers applied in automobiles like, AD Series - Adjustable Shock Absorbers, Auto and Truck Adjustable Shock Absorber for Isuzu, Front Shock Absorber (Volkswagen Golf III), Front-Right Shock Absorber for BMW3, High Tensile Motorcycle Compression Shock Absorber Spring and Air Adjustable Shock Absorbers - Advance Auto Parts.