Performance characteristics of a multicelled, electrostatic, triode, getter-ion pump are described, with data on pumping speeds vs pressure for Ar, N2, O2, and H2, starting characteristics, pressure measurement, ultimate pressure, residual gas composition, and operating life. A 6-in.-diam orifice pump has a baffled N2 pumping speed of over 1700 liter/sec below 5 × 10−7 Torr and pumps argon at 25 liter/sec. Pumping speeds higher than those predicted by the titanium sublimation rate are observed for N2, O2, and H2 at pressures above 10−6 Torr. At 10−3 Torr, the N2 speed is higher by a factor of 38. For N2 and O2, the higher than expected pumping speed is attributed to direct interaction of the gas with the sublimator, which operates at a temperature at which the interaction rate is maximal.