For example: Agilent E4440A or Anritsu 68369
Electrometers / High Resistance Meters / Meggers
Clarostat 240-C
Clarostat 240-C Power Resistor Decade Box, 0 to 999,999 Ohms, Six Decade Steps
Manufacturer: Clarostat
Keithley Instruments 6512
Keithley 6512 Programmable Electrometer
Manufacturer: Keithley Instruments
