These three brass plates are by "Hevi Duty Electric Co., Milwaukee, Wisconsin" (printed on bottom of plate).
Printed at top of each plate: "Automatic Electric Water Heater, Storage Type." Below this are two columns, with empty brass rectangles for information to be recorded regarding test pressure, water temp., volts, etc., plus a blank serial number rectangle.
All three plates are the same: brass printing and border with green background; two screw holes centered on each side; measures 3"x2-1/2". Vintage 1951. (Note: Plate color is green, as shown in photo of 3 plates.)