A thermocouple is a device consisting of two different conductors (usually metal alloys) that produce a voltage proportional to a temperature difference between either end of the pair of conductors. Grounded Type is more sensitive to temperature, can help to measure temperature fasterly.5 x 100mm sensor PT100 Type thermocouple with flexible spring built in.3 terminals for easy connection. Temperature measurement range is from 0 Celsius to 400 Celsius degree. Widely used for industrial or laboratory to Test equipments temperature.