A thermocouple is an electrical device consisting of two different conductors forming electrical junctions at differing temperatures. A thermocouple produces a temperature-dependent voltage as a result of the thermoelectric effect, and this voltage can be interpreted to measure temperature. Thermocouples are a widely used type of temperature sensor.  

Ideal for measuring boiler flow and return temperatures. Measures the temperature of pipes in refrigeration and H&V systems. The sensor is in the clamp jaw which fits around the pipe.
 

Specification:
Temperature range -50 to 100°C
Dimensions Maximum Φ30mm