DT-700 Non-aqueous conductivity meter
DT-700 Conductivity Non-aqueous Probe
This electric conductivity meter measures electric conductivity of non-aqueous solutions, low and non-polar liquids when dielectric constant is very small.

From pure toluene to distilled water while using this one instrument.
Quality control of non-polar liquids when they contain either ionic or surfactant.
Calibration by user is available when fixed resistors set plugged in instead of the probe.
Easy to take apart and clean while taking probe apart by removing outer cylinder electrode.
References
There are many published papers describing application of this instrument for characterizing wide variety of non-polar liquids and dispersions. Accordingly, section on bibliography contains their list. Here is a link to couple of them:
Characterization of a surfactant adsorption from the non-polar liquids into porous materials is one of the most novel, here is the link :