- 4 Unusual Measuring Instruments...
- Group of Ampere and Voltmeters...
- Radio-related Service and Laboratory Equipmen...
- 3 Oscilloscopes and 1 Measuring Instrument, c...
- Telefunken Type K.W. 61g Wave Meter, 1917...
- 19 Measuring Instruments...
- Early French Wavemeter, c. 1918...
- 5 Radio Engineering Measuring Devices...