[Phil G4SPZ]

Thanks for the reminder, Ian - I’d forgotten how interesting that old thread became! However, that thread covered Universal AvoMinors.

The instrument in your photo is a DC AvoMinor of the earliest pattern, with the straight-sided case and small zeroing knob for the resistance range. I’ve a couple of these, dating from 1934 or thereabouts. There are several variants of the DC AvoMinor and it almost warrants a thread of its own. I bet Dave knows all about them...!