The liquid spring strut was conceived over 20 years ago to fulfil the need of providing a more reliable and better performing suspension system for off-highway mining trucks. The strut was constructed similar to a conventional shock absorber, except it was filled with pressurized compressible fluid as opposed to mineral oil. This configuration resulted in a unique component capable of supporting vehicle load and providing damping in a single element. The future potential of this technology was recognized for other markets and LiquidSpring Technologies, Inc. (LST) was founded to further its development. The original strut worked very well for off-highway mining applications; however, it was not very suitable for other applications because of its fixed preload and damping characteristic. Continued innovative efforts by LST resulted in technological breakthroughs which allowed the strut to exhibit a broad range of stiffness and damping characteristics and hence be usable for on-highway applications. The key, patented breakthrough was coupling the strut with an additional fluid volume and controlling the fluid interaction between each component thus enabling the strut to have variable stiffness and damping. This aspect is truly unique and sets this technology apart from other suspension systems. The liquid spring suspension systems developed by LST are called CLASS® or Compressible Liquid Adaptive Suspension System. In 2004, LST formed a subsidiary LiquidSpring LLC to focus on commercializing CLASS® products while LST continues its research work advancing liquid spring technologies. LiquidSpring LLC has commercialized CLASS® product for several light and medium duty truck applications such as ambulances and shuttle buses. The products have demonstrated significant ride and handling performance improvements over conventional steel and air spring suspension systems based on ride and drive evaluations at OEM’s, dealers, and customers. Further refinements in its configuration and control have resulted in reduced complexity and improved performance. LiquidSpring LLC continues to develop product for other Class 3-8 on-highway truck and military markets as well as providing sales, application, manufacturing, distribution, and service of CLASS® product.