The General Tools MMH800 4-in-1 Pin/Pad RH Moisture Meter is ideal for locating water leaks and measuring moisture content of wood, drywall, plaster walls, carpeting, flooring, brick, grout, soil, paper or powders. High l...

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Product Review

The General Tools MMH800 4-in-1 Pin/Pad RH Moisture Meter is ideal for locating water leaks and measuring moisture content of wood, drywall, plaster walls, carpeting, flooring, brick, grout, soil, paper or powders. High levels of moisture that go untreated are the main cause for harmful mold growth in the home. This tool features both pin-type and pinless (flat pad) surface sensors. With the MMH800 combo moisture meter, scanning large areas of drywall and wood is easy with the pinless pad sensor. Once moisture patches are detected, flip open the cap to expose the pin sensors for more exact moisture content readings. It features two displays; one for moisture content and one for ambient temperature and humidity. The unit provides a moisture level range of 5-percent to 50-percent in wood and 1.5-percent to 33-percent in building materials, and offers an audible indication of moisture level and storage of moisture level readings. It holds moisture level readings for convenient viewing later. The tool also has an auto diagnostic check and auto power off. Powered by a 9 volt battery (included). The unit also comes with a lanyard, 2 sets of spare pins and a user’s manual.

Moisture Measurement Ranges:
5 to 50% moisture (wood);
1.5 to 33% moisture (building materials)
Moisture Measurement Accuracy: ±3%
Moisture Measurement Resolution: 0.1%
Humidity Measurement Range: 25 to 95%
Humidity Measurement Accuracy: ±5% from 0° to 40°C
Temperature Measurement Range: 32° to 140°F (0° to 60°C)
Temperature Measurement Accuracy: ±2°F (±2°C)
Operating Temperature: 25° to 45°F (-4° to 7.2°C)
Operating Humidity: 95% max
Storage Temperature: 23° to 140°F (-5° to 60°C)
Storage Humidity: 95% max
Auto Power Off: After 3 minutes of inactivity
Dimensions: 7.13 x 2.17 x 1.57 in. (181 x 55 x 40mm)
Weight: 4.06 oz. (115g)
Power Source: 1 “9V” battery (included)



  • HUMIDITY SENSOR: Our combo meter tool can quickly determine what level of remediation is needed to keep your family safe from black mold. High levels of dampness that go untreated are the leading cause of harmful fungus growth in the home.
  • WATER LEAK DETECTOR: Finding the moisture content in your floors, plastered walls, and wood is the first step in early prevention. Continuously check and test suspicious water stains around the house so you can determine if the area is wet or dry.
  • MOISTURE READER: The mold test features 2 dedicated displays, moisture percentage, ambient temperature, and relative humidity. Our mildew scanner includes audible and visual indications of high, medium, and low moisture levels with a °F/°C switch.
  • MOLD TESTER: This tool features both pin-type and pinless (flat pad) surface sensors for an accurate test read on larger areas. Once moisture patches are detected, flip open the cap to expose the pin sensors for more exact content readings.
  • GENERAL TOOLS: We're a recognized leader in designing and developing specialized precision tools dedicated to delivering exceptional customer service. We encourage artisans and DIYers to work smarter, measure better, and repair more productively.

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