D01903 is a Duratool Digital Probe Thermometer. It is used to measure the temperature of a variety of surfaces, such as motors, transformers, and process lines. The thermometer features a -50 to 750°F (-45 to 400°C) temperature range, a resolution of 0.1°F (0.1°C), and a single button control for easy operation. The thermometer also has a large backlit LCD for easy readability, as well as a range alert for over/under temperature limits. It is powered by a 9V battery.