Thermocouple Thermistor Sensor Probe.  -20 to 420 deg C Range.

PID Temperature Controllers can be used in conjunction with a relay and a temperature probe to control the your kegerator and fermentation temps. You can also integrate a PID controller into your brew system to control mash temps and more.

MYPIN Waterproof Stainless Steel PT100 RTD Thermocouple Thermistor Sensor Probe, Thread with Insulation Lead Wire for PID Temperature Controller Control K Type Probe 2M(6ft) (Temperature Rang: -20~420°C)

Inkbird ITC-308 – Dual Stage Digital Temperature Controller | Review | Inkbird Deals