DirecTorr Gold oil is a synthetic hydrocarbon oil put through a double molecular distillation process. Gold oil is extremely stable under high temperature, has excellent resistance to chemical attack and provides superior protection for the pump's internal metal components. Recommended for corrosive gas and vapor applications regardless of the pump used. Oil is triple-distilled, severely hydrotreated oil designed to resist breakdown at the higher RPMs and operating temperatures of direct-drive vacuum pumps. Premium Oil enables Welch direct-drive vacuum pumps to maintain the highest performance.