The TRU 937 (Temperature Reference Unit) supplies a stable and accurate 0°C or elevated Reference Temperatures between 45°C and 70°C. It is a self-contained all solid state unit using peltier technology which provides maintenance free operation. The TRU 937 features rapid cool down from high ambient temperatures and is stable within 10 minutes from switch on. An alarm will be activated should the reference temperatures deviate by more than the user definable span. Thermocouple Reference Junctions are located in a reference block and connected to their marked input and output terminals in an isothermal enclosure. The uniform temperature throughout the enclosure ensures that no thermoelectric EMFs are generated at the terminals. One advantage of the TRU 937 is that the user need not be concerned with the supply and installation of reference junctions since it is only necessary to connect the thermocouple compensation cables to the input terminals and the measuring instrument to the output terminals of the TRU 937. There are two models, the TRU 937/50 with up to 50 junctions with a single terminal cover door, and the TRU 397/100 which has doors on the front and rear, as shown in the photograph.