The Granville-Phillips® 475 Convectron® Vacuum Gauge Controller combines with the industry-standard Series 275 Convectron® gauge to provide high performance vacuum pressure measurement using a unique variation of thermal conductivity The Convectron® gauge is a convection-enhanced Pirani design vacuum gauge that features individually calibrated gauges  temperature compensation and convection technology for increased accuracy and repeatable vacuum measurements over seven decades from 1x10-4 Torr to Atmosphere