In the package of a Bulk, NTC thermistors are contained. It is included in the Probe package for your convenience. NTC thermistors have a resistance tolerance of ±0.05°C in order to function properly. NTC thermistors should be set to 0°C~50°C temperature to ensure reliable performance. Temperatures below 50°C allow NTC thermistors to operate reliably. Optimal reliability requires a minimum temperature of 0°C for NTC thermistors. It is imperative to connect the 2 pins of the NTC thermistors in order to make it work.