Gay-Milano tracking voltmeter

This Italian DVM is built very compactly. It has four ranges, selected by push buttons:

• 1, 10, 100 and 1000 V

I acquired this digital voltmeter through a swap deal with a fellow hobbyist. No manual came with it. Unfortunately, the mains cord didn't come with it, either. As it has a very non-standard mains receptacle, I wasn't able to hook it up and test it yet.