Harvest Pro® Commercial RVD-5 & RVD-4 Vacuum Pumps (115 V, 60Hz, 1 Phase) are built to last. These rugged and reliable vacuum pumps are designed for long life with continuous use. The Harvest Pro® RVD series of vacuum pumps are specifically suited for botanical extraction, like distillation, freeze drying and a number of other processing techniques. Easily control the ultimate pressure of this dual-stage rotary vane vacuum pump thanks to its adjustable gas ballast. A built-in backflow preventer helps avoid oil contamination in case of an unexpected shutdown. Plus, the low decibel rating (56-58) makes it one of the quietest rotary vane vacuum pump available. Displacement speed at 60Hz: RVD-5 = 9.6 m3/h (5.6 cm), RVD-4 = 7.2 m3/h (4.2 cfm).