These thermometers, fabricated of quality materials, work on a conduction-radiation principle. The base of the unit is placed on the surface to be measured. Heat is transferred to the inner chamber of the unit, which contains a bimetallic sensing element. Radiation from the base inward causes the sensing element to react, with resulting dial readout.

Easily and quickly installed. For nonhorizontal areas,the bottom of the unit is coated with a thin layer of silicone grease and the unit is pressed into position. The grease will hold the thermometer in place on ferrous surfaces and a magnet and leaf spring holds the instrument firmly against the surface. These instruments are fully enclosed to protect the bimetal from dirt and dust.

All standards used for calibration are certified every 6 or 12 months depending on the type. These standards are traceable either to the National Institute of Standards and Technology (NIST) or to natural physical phenomena.

Certification traceable to NIST in accordance with ANSI/NCSL Z540-1 is available. Two types of certifications are available, with or without logged points. The certification with logged points provides both before and after readings. Calibration temperatures are of the calibrator's choosing, unless otherwise specified by the customer. The certification without logged points provides low, medium and high points of the calibrator's choice. The points calibrated are not logged and will not be recorded.

Both certifications include traceability information on the standards used in calibration. This information consists of: Type of standard, manufacturer, model number, serial number date calibrated, due date and NIST traceability number.