Moisture content measurement meters
Delmhorst Instrument Co., 201-334-2557;Lignomat USA, Ltd., 800-227-2105; and
Wagner Electronic Products, Inc., 503-582-0541.
The meter's probe has two electrodes (pins) that should be at least two-inches long and coated with an electric insulation. This type of probe is electrically conductive at the tip and therefore senses moisture only at the probe's tips. Surface moisture or moisture in contact with the pins' shank should not effect the reading. [http://www.buglaw.com/news/attachB.html Jan/02]
Northern Hardwood Initiative gives very good consideration to resistive and dielectrial meters.
Web Links:
Moisture Content Measurement- An excellent, practical article on practical MC measurement.