This listing includes pumping system (retail $25,100) and the controller (retail $3,050). -Granville-Phillips 835 VQM (Vacuum Quality Monitor) DPS (Differential Pump System) Part #835901-DPS-3M3-1-Granville-Phillips 835 VQM (Vacuum Quality Monitor) Controller #835500-U1-1 The 835 VQM is a mass spectrometer that operates from UHV to 10-5 Torr and accurately measures the gases in the vacuum chamber. The 835 VQM Differential Pump System delivers the advantages of the 835 VQM at higher pre
