Would have been used in electrical engineering laboratory experiments. Slip inside of lid indicates that the instrument would have been checked at times for accuracy of readings. This was checked and passed on 28 November 1959.Wattmeter, portable, in varnished wood case with leather strap handle. Hinged lid with calibration chart inside the lid. Range - 0 to 1.5. Voltage ranges: 150v; 300v; 600vSerial No 2927 Dated: 28/11/58 Signature: J J Abbott A J William Electrical Instruments, Melbourne, C.1. Dymo tape on front side: WATTMETER 0 - 1.5 kwwattmeter, portable, electrical engineering, experiments, dynamometer type, scientific instrument