Introduction to the OHR-C03 Process Calibrator, testing the voltage, current and resistance functions.
Non-affiliated links;
Aliexpress purchasing link;
https://www.aliexpress.com/item/1005010706918385.html
EEVBlog on OHR-C03;
https://www.eevblog.com/forum/testgear/ohr-multifunction-process-calibrators-(ohr-c03)/msg5764671/#msg5764671