PM2434 DC uV meter
This is a Philips DC microVolt meter. It is no longer in my collection. I gave it away to a student who needed something for measuring very low voltage. If you want this resolution for a DMM you need a 5.5 or 6,5 digits version. But with 10 uV full scale these old analog meters are a nice affortable alternative.
I never found the manual for this meter.