ANTIQUE AMBU TYPE E TRUCK AUTOMOBILE AMBULANCE VOLTMETER
A very unusual multifunction automotive meter, probably 1930s. Believed to be a meter for commercial vehicles such as trucks and ambulances. Made by American Bureau of Engineering (Ambu) Chicago. Featuring a voltmeter with a scale of plus and minus 2.5 and 25 volts, four binding posts and a fuse holder.
In addition there are three rings adjusted with three tabs around the bezel. These calibrate five settings around the dial labeled "Engine Running Lamps Off," "Upper Key No.," Lower Key No.," "Engine Not Running Lamps On," and "Engine Not Running Lamps Off."
The metal tag on the meter indicates it is "Type E Number 149148." The case appears to be cast aluminum with a bakelite or similar material base. 7 inches by 7 inches by 3 inches, weighs 4 pounds 5 ounces.
Very good condition with original glass and needle, original Ambu label, all adjustments and indicators appear to be working. Paint loss consistent with age, no cracks in case. Sold as untested, functionality not guaranteed but is most likely working.