Ohms: Which products are recommended for measuring in the range of 2 - 50 micro-ohms?

The best solution involves two instruments, a Keithley Model 2400 SourceMeter instrument for sourcing current and a Keithley Model 2182 Nanovoltmeter for measuring volts using an alternating polarity technique. If the device under test can tolerate (or the experiment requires) current higher than 1 Amp, the 2400 can be substituted with a 2420, 2425 or 2430 SourceMeter instrument, depending on the exact current sourcing requirements.