OK. Simpson 3/64 DIN M135-0-0-11-0 non backlit Allied Electronics # 919-5000 $63.32 This is a 200mV unit. You have to make a current shunt for it to read 4 Amps and you need a separate 5VDC power supply to power it.

Or you could make a calibrated dial using your DVM so that the knob setting is accurate. Lots easier.

John