Vintage Meter by A & M INST. 0-30 DC, Model 267-033, 20 uA Full Scale, TESTED NOS
Diameter at Flange: 2.75"
Appears to have never been used.
Full Scale Current: 20 Microamps
Operates very smoothly - no sticking or dragging
Comes with connection and mounting hardware - see photo 1
Requires external shunt to read in DC Current