1 Liter Premium Oil for Direct Drive Vacuum Pump Features: Low vapor pressure Excellent resistance to heat Designed for direct drive vacuum pumps This triple-distilled hydrocarbon oil is derived from hydrotreated base stock for high performance in vacuum pump operation at elevated temperatures. Welch Premium vacuum pump oil resists breakdown in the high RPM operation environment of direct drive pumps. Enables direct drive pumps to maintain the highest vacuum performace over time.