The TH-21 Series thermistor probes from Omega are constructed with the 55000 Series glass encapsulated thermistor elements, which the company says provides excellent stability and accuracy. With a maximum continuous temperature rating of -112°F to 392°F, and intermittent operation to 482°F, these thermistor sensors can be used in applications previously out of reach of epoxy coated thermistor sensors. The probes can be ordered in any length, but the company highly recommends a minimum immersion depth of 1.5 in. Short probes run the risk of error due to stem conduction effects.