MRH3 - Moisture and Humidity Meter


The Tramex MRH3 Moisture and Humidity Meter is a hand-held digital moisture meter calibrated for most building materials. It also attaches to an optional plug-in Tramex Hygro-i2 ® relative humidity probe and heavy-duty pin type electrodes. Suitable for many industries including Water Damage Restoration, Flooring, Indoor Air Quality, Home Inspection and Pest Control.



  • Digital, non-destructive moisture meter.
  • Deep signal penetration to over 25mm (1") into the materials being tested without the need to damage the surface. Signal penetration depends on material being tested and meter setting.
  • Specific gravity adjustment for wood species. 
  • External Rubber electrodes make direct contact with the material being tested for best sensitivity and repeatability.  
  • Wide range of readings for wood of 5% to 30% and 0 to 100 comparative for all other materials.
  • Backlit, large, clear, easy to read LCD display.  
  • “Hold” function enables user to "freeze" the reading. Useful for taking readings when the meter face is not visible.
  • Switchable "On" or "Off" audio warning tone.    
  • Automatic power cutoff switches "Off" when not in use.
  • Automatic default to last user setting when switched back on.
  • Battery operated (included).
  • Attaches to plug-in wood probe (optional).
  • Attaches to plug-in Tramex Hygro-i2 ® relative humidity probe for relative humidity, temperature, dew point and mixing ratio readings (optional).


Product Order Code: MRH3


The MRH III operates on the principal of non-destructive impedance measurement. Co-planar electrodes are fitted on the base of the instrument from which low frequency signals are transmitted into the material under test, measuring the change in impedance caused by the presence of moisture. This reading is translated by the instrument into a moisture content reading.


Hygrometer mode:


When the Tramex Hygro-i2 ® relative humidity probe is plugged into the MRH III, it automatically changes to Hygrometer Mode. The Tramex Hygro-i2 ® provides the ideal solution for measurements of ambient relative humidity, temperature and dew point conditions within the building structure and in structural materials such as concrete flooring, walls etc.




  • Size: 6" x 3.5" x 1.5" (150mm x 85mm x 38mm)
  • Weight: 8.47oz (240g)
  • Construction: ABS
  • Body Power: 9 volt PP3
  • Battery (included)
  • Display: Digital / Backlit Depth of penetration: up to 1¼"(30mm)(In wood, drywall)


Measuring range:


  • Reference scale for building materials: 0 to 100
  • Relative Humidity (with optional Hygro-i2 ® probe): 0 to 99%
  • Wood Non-invasive Mode: 5 to 55% MC (at SG of 0.3)
  • Wood Invasive Mode (with optional wood pin probes): 7 to 40%MC

Related Products

Building Survey Inspection EZ Kit


This complete moisture and humidity testing kit features the multifunctional Tramex MRH III digital moisture meter allowing for non-invasive testing of moisture conditions in numerous building materials such as drywall, wood, plaster, brick, ceramic tiles, resilient flooring, laminates and roofing. 

Flooring Master Kit


The ultimate kit for pre- & post-application moisture testing of concrete slabs, wood and various other floor covering materials.

Relative Humidity Probe For MRH III / CMEX II


When the Tramex RH probe is plugged into the MRH III, the instrument automatically changes to hygrometer mode. The Tramex RH probe provides the ideal solution for measurement of humidity, temperature and dew-point in structural materials such as concrete flooring, walls etc., as well as the environmental conditions within the building or structure.

Heavy-duty Pin-type Wood Probe with Cable and Pins


Heavy-duty Pin-type Wood Probe with Cable and Pins for use with CMEX2, MRH3 & PTM.