The MKS Graville Phillips 274 Nude Bayard-Alpert Ionization Gauge is a rugged, open gauge with broad-range operating pressure abilities, Thoria-Coated Iridium Filament, KF40 NW40, 1×10^-3 to 2×10^-11 Torr Pressure Range, Maximum Bakeout Temperature: 450 °C.

The Granville Phillips 274 Ionization Gauge, with an x-ray limit of 2x10^-11 Torr, provides reliable pressure measurement from 1 mTorr down to 2x10^-10 Torr, with reduced performance at pressures lower than 2x10^-10 Torr. The Granville Phillips 274 utilizes an extremely thin collector which lowers its x-ray limit to 5x10^-12 Torr. As a result, it can measure pressure from 1m Torr down to 5x10^-11Torr, with reduced performance at pressures lower than 5x10^-11 Torr.

Properly mounted nude gauges, where the grid structure protrudes into the vacuum chamber, offer the lowest error in terms of the local vacuum pressure being the same as the chamber pressure. The Granville Phillips gauge is easily interfaced with the Varian's Agilent XGS-600 gauge controller for integration into a variety of vacuum systems, or for use as a stand-alone pressure measurement tool.