Dwyer Instruments, Inc. manufactures and offers many temperature measuring products that use a thermistor as the sensing element.
Thermistors are based on the principal that the electrical resistance of semiconductor materials is a function of the temperature. Thermistors work well over smaller temperature ranges with better accuracy than (RTD) but are very non-linear. They also generally offer better response times. Thermistors have much higher resistance values than RTDs, with ranges typically ranging from 100 ohms to 100 megaohms.