VU level meter and 600 ohm switched attenuator set

Description

This is a VU level instrument for 600 ohm lines. The  large Weston meter has dual scales: VU (-20 to +3) and Modulation (0 to 100%). It employs a nee TRS input connector with grounded shield twin lead. Note there is no zero dB on the attenuator. As customary, the minimum attenuation is 4 dB (IRC Type C stepped attenuator). So reading zero VU is +4. The step size of the attenuator is 2 dB. Note the first 2 photos are Zero VU and -2 VU corresponding to one step of the attenuator. The 600 ohm switch on the front panel places that load before the attenuator or after the attenuator.
Really cool, functional vintage item.
It is stamped June 1950 USN on the inside back case.