A Time electronics DC voltage potentiometer, it all turns on and outputs voltages fine, unfortunately I am not convinced it is as accurate as it says but it may be my digital multimeter.
Spec'ed at 0.02% voltage range 9.999V to 999.99uV
Battery charges up still even although it has been in my shed for many years.
Sold as seen.
Postage is for UK mainland only others please ask for quote.