Shown is a General Electric I-30-A that was manufactured during WWII. Aluminum was in demand for the war effort, so GE used brass for the register, metal alloys for the meter's grid and case. The nameplate is made out of a thick, compressed paper substance. The register is a specially designed type with reverse dials with the last dial indicating 1/100th, next dial 1/10th, then 1's and 10's dials. Register ratio is 1 & 2/3. 5 amps / 120 volts.