Pfeiffer Inland 19 General Purpose Mechanical Pump Oil (sold here by the 1 liter bottles PN PK005632-T) is quality mechanical vacuum pump oil for the ultimate performance of your Pfeiffer Rotary Vane pumps and Roots Blowers. Pfeiffer Inland 19 Oil is specially prepared by Pfeiffer to meet the Rotary Vane exclusive specifications. We recommend that you change your vacuum pump oil at least every 3 months to prolong the life of your vacuum pump.