I'm looking to find...or information on this meter that had 3 terminals, common HV , LV

It goes on the BC 227 receiver

It was used to check on the voltage for the batteries for this SCR 203 set up.

Schematic only gives the is-116 for the meter...no other info

Hoping someone has a Signal Corp listing of component parts that include meters

Thanks

Paul

N6FEG