This is a Milli-Volt and Milli-Amp Source for Calibration of Temperature Measurement and Control Instruments using Thermocouples. There is also a Passive Variable Resistance Source for Simulating a PT-100 RTD Sensor.
This calibrator was a simple solution i built. This instrument itself was calibrated by Instruments like the Calibrators from Omega which are the best you can get.
You will learn more if you make your own tools and instruments and use it alongside the professional tools you buy. Some Jigs and Fixtures are custom developed even today for testing and troubleshooting. Building your own equipment will keep your skills updated and lubricated.