These Teledyne Hastings Digital VT thermocouple vacuum gauge controllers are matched for the DV-4 thermocouple vacuum gauge tubes (Stock Number 55-288DV4, Operates on 115 VAC). They measure pressure between the range of 0.01 and 20 Torr. The Teledyne Hastings Digital VT thermocouple controllers are self-contained instruments that offer extreme versatility for most vacuum applications. The electronic design assures long life and minimal maintenance. Compact Digital VT Models are ready for mounting onto a panel. Teledyne Hasting thermocouple tubes are also available but sold separately.