The 100006842 Nude Tube Vacuum Sensor features a Yttria-coated Iridium filament for a 10-2 - 10-11 Torr vacuum measurement range and a 2.75 in. CF flange fitting. This Bayard-Alpert style ionization vacuum sensor, which uses a fine wire collector located in the center of a grid. Because of its small area, few x-rays hit the collector, and a vacuum gauge can measure pressures to very low levels. Because the sensing portion of the tube is located within the vacuum system and experiences the system true pressure, nude tubes give a representative pressure measurement and respond more quickly than a glass envelope sensor to pressure changes.