Velvac's height control valves are designed and produced by an ISO 9001: 2000 certified facility to OE specifications, and are a direct replacement for all makes of cab air suspension and chassis applications. They offer non-drilling, bolt-in installation, Shear-Seal® Design which wears in, not out, hardened valve components that resist wear from air system contaminants, along with many other features that ensure a long service life.