A pass-through wattmeter is a type of device used to measure and monitor electric power. Pass-through wattmeters measure power using the effect of the magnetic field generated by the passing current.
The item for sale is a pass-through wattmeter manufactured by Microwave Devices Div. USA. The condition is clean with no overall scratches, but there is a slight dent on the lid of the cylindrical cabler. However, it can be repaired by opening the housing. There are no electrical problems.