This vintage instrument is a DC voltmeter with the NSN 6625-99-012-0394  an instrument used to measure direct current voltage..

Meter has Internal 600k load impedance

These voltmeters are rugged and reliable, designed for military or industrial use.

It’s still functional, it would be a valuable tool for electronics work or restoration projects. Older instruments like this have high-quality components and craftsmanship.

1mA full scale deflection

It is a 0 to 600VDC moving coil voltmeter drawing 1mA for full scale deflection. 

It was made in 1967

The device was manufactured in the United Kingdom and is a rare example of military-themed collectable test equipment.

Panel size mm hole would be 90mm diameter (3.5") it is 2 inches deep including terminals.

WORKING USED RELIC TESTED SEE IMAGES

Case is Plated steel

Weight 420g

Location 6 mum 12 left green box