Cornerstone Valve is a U.S. manufacturer of engineered ball valves designed for severe-service applications across refining, oil & gas, petrochemical, power generation, mining, waterworks, aerospace, and defense industries. Since 1990, the company has specialized in metal-seated, trunnion-mounted ball valves engineered to deliver reliable, zero-leakage performance in high-pressure, high-temperature, and abrasive operating environments. Cornerstone Valve develops application-specific valve solutions from concept through finished product, combining advanced engineering, flexible manufacturing, and rapid response to customer requirements.