This is a high quality platinum thermistor SF-R PT100 high temperature sensor with a range between -50C - 350C.
It is used as the Overlord 3D Printer temperature sensor. The resistance value it reads inside the nozzle is fed to the mainboard which converts the raw data in to a temperature reading. The printer can then adjust the temperature of the nozzle. It is compatible with both the Overlord and Overlord Pro.