Celestron's Thermistor for Smart DewHeater Controllers is the perfect tool for any digital astronomer. This device uses a thermistor to measure the temperature of the telescope and its environment to ensure optimal performance. It is designed to work with Celestron's Smart DewHeater Controllers, allowing you to make precise temperature adjustments to your telescope and accessories. With this device, you can ensure your telescope is always working at its best, no matter the conditions.