Question: Need models to replace the 175 auto range multi meter and 179A TRMS multi meter
Answer: These units have had several replacements in our portfolio since they went obsolete.
Our current 6.5 digit DMM is the DMM6500:
https://www.tek.com/en/products/keithley/digital-multimeter/dmm6500
If you are looking for better performance (7.5 digit) on the same, modern platform, we have the DMM7510:
https://www.tek.com/en/products/keithley/digital-multimeter/dmm7510
Our DMM with the best AC measurement performance is Model 2001:
https://www.tek.com/en/products/keithley/digital-multimeter/2001-series