Tokico is one of the worlds leading manufacturers for Shocks and Struts today.There non adjustable shocks,The HP-Series Shocks, also known as the famous "Blue Shock", continues Tokico's tradition of excellence. These HP-Series Shocks provide superior handling and exceptional ride quality by utilizing the Tokico piston and valve designs. Springs, suspension components and pivot bushings allow suspension movement, but something is needed to eliminate excess, Without proper control, suspension motion will become excessive and even violent. If springs are the heart, then shocks can be considered the brains. HP-Series Shocks use hydraulic friction to damp out or resist suspension movement. While springs are "load sensitive" devices, the HP-Series shocks react to suspension velocities. HP-Series Shocks remove kinetic (or movement) energy from the suspension and convert it into heat, which is dissipated into the air. The HP-Series Shocks work in two directions.Compression (or closing) direction works with the spring to reduce bottoming and help keep the tire in contact with the road surface. Rebound (or extension) controls the release of spring energy as it returns to its normal height, so your Acura TL doesn't bounce or float. Excessive shock control delivers a harsh ride and reduced traction,while too little control allows the chassis and tires too much movement. The HP-Series Shocks unprecedented valving curves and velocity sensitive characteristics stabilize the suspension system, preventing excessive and even violent movement, By minimizing low speed damping force and greatly increasing damping at medium and high piston speeds, improved steering response, tire adhesion and handling can be obtained. These HP-Series Shocks are perfect for those looking for the best in overall performance and ride quality.