ANRITSU ML428B Interference/Field Strength Meter 9khz~30Mhz
It is enables measurement of the field strength of general broadcasts and radio communications.
It is perform measurements of interference waves in accordance with CISPR, VDE, FCC, or other specifications. 
The ML428B possesses a local synthesizer and high-precision sine wave comparison oscillator to obtain data with excellentrepeat-ability.
The built-in microprocessor allows level calibrations and attenuator operation to be automatically performed to enable direct reading of the field strength and efficient measurement.
It is made in Japan. Pull out of working environment and works fine. I have little experience with this type of equipment, so i only can tell what the pre owner told me.