Pfeiffer Vacuum, TMH 261-250P, Turbo Molecular Pump, w/ TC600 Controller, NOS. Pfeiffer Vacuum, TMH 261-250 P, Turbo Molecular Pump. NEW – Old Stock. Has Not Been In Service! Has Not Been Installed / Mounted, Has Not Been In Service! Shelf Spare from Perkin Elmer Liquidation In Boston. (ICN Grams / Shelf L). Please Look at Photos Closely! Please Scroll Down for Large Photos.