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Extech MO55A Combinaton Pin/Pinless Moisture Meter

Extech Instruments
SKU: EXTEMO55A
  • Includes dual pin and pinless moisture measurement modes
  • Automatic calibration in pinless mode
  • Displays moisture levels in wood and building materials
More Info
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Extech MO55A Combinaton Pin/Pinless Moisture Meter

The Extech MO55A Combination Pin/Pinless Moisture Meter provides fast, reliable readings across a wide range of materials by using both pin and pinless measurement methods. This allows you to switch easily between surface scanning and deeper, more precise probing, depending on the job.

To support clear and efficient use on site, the meter features a high‑contrast colour LCD with a backlight, ensuring readings remain easy to see in any lighting condition. Moisture levels are displayed using intuitive droplet icons alongside digital values, while the built-in audible alert increases in frequency as moisture rises. This gives you immediate feedback without needing to constantly check the screen, helping you work more efficiently on busy jobs.

The pinless method is used to scan up to 25 mm below the surface without causing damage – ideal for finished materials, flooring, tiles, or quick inspections under carpets. When greater accuracy is required, the pin method is able to measure moisture content in wood (5.0% to 50.0%) and other building materials (1.5% to 33.0%) using replaceable 8 mm electrode pins. With both options available, the MO55A is particularly useful for restoration work, leak detection, and monitoring moisture behind walls or in ceilings after water damage.

Built for practical, everyday use, it features automatic calibration in pinless mode and a clear battery status indicator. It also features auto power-off to help conserve energy and extend battery life on longer jobs. Durable and lightweight, it’s well suited to site work, withstanding drops and vibration in line with professional standards.

Part number: MO55A

Key Features

  • High-contrast colour LCD with backlight for easy viewing in any lighting condition
  • Displays moisture levels in wood and building materials such as wall board, sheet rock, cardboard plaster, concrete, and mortar
  • Pinless moisture measurement depth to <25 mm (1 in)
  • Pin measurements for wood (5.0%–50.0%) and building materials (1.5%–33.0%)
  • Audible Alert Tone rate that beeps faster as the moisture level increases
  • Complete with pins (2 installed and 2 spares), protective cap, and batteries

What's In The Box?

  • Protective cap
  • 3 × AAA batteries
  • 2 × replacement pins
  • Quick start guide
Specification
  • Display: Backlit Colour LCD
  • Sensor Type: Replaceable threaded contact pins, 8 mm (0.3 in); non-penetrating electromagnetic sensor pad
  • Electrode Pin Length: 8 mm (0.3 in)
  • Electrode Pins: Integrated, Replaceable, 8 mm (0.3 in)
  • Measurement Principle: Electrical resistance (pins); Capacitance (pinless)
  • Measurement Depth: Pinless < 25 mm (1 in)
  • Auto Calibration: Pinless mode in open air
  • Measurement Indication: Digital, Moisture Droplet icons and Beeper for High, Medium, Low indication
  • WME Moisture Content (Pin):
    Wood: 5.0% to 50.0%
    Other Building Material: 1.5% to 33.0%
  • Measurement Range (Wood) – Pin:
    Low: 5.0% to 11.9%
    Medium: 12.0% to 15.9%
    High: 16% to 50%
  • Measurement Range (Building Material) – Pin:
    Low: 1.5% to 16.9%
    Medium: 12.0% to 15.9%
    High: 20% to 33%
  • WME Moisture Content Basic Accuracy (Pin) ±(3% + 5 digits) at 22°C to 25°C (72°F to 77°F)
  • WME Moisture Content Max Resolution (Pin): 0.1%
  • Relative Moisture Content (Pinless):
    Wood: 0.0% to 99.9%
    Other building materials: 0.0% to 99.9% up to 25 mm (1 in) deep various with material under test
  • Pinless Measurement Range:
    Low: 0.0% to 16.9%
    Medium: 17:0% to 29.9%
    High: 30.0% to 99.9%
  • Relative Moisture Content Max Resolution (Pinless): 0.1%
  • Auto Power Off: After approx. 3 minutes.
  • Battery Type: 3 × 1.5 V, AAA batteries
  • Power Consumption: Operating Current: < 15 mA (Average), APO < 10 μA
  • Battery Status Indicator:
    3-bar battery icon (100% to empty)
    Full above 4.5 V
    Two Lattice 4.2 V to 4.5 V
    One Lattice 3.9 V to 4.2 v
    Empty Frame 3.6 V to 3.9 V
    Flash Frame 3.3 V to 3.6 V
    Shutdown below 3.3 V
  • Operating Conditions: 5°C to 45°C (41°F to 113°F); < 80% RH
  • Storage Conditions: 0°C to 50°C (32°F to 122°F); < 85% RH
  • Operating Altitude: 2000 m (6562 ft)
  • Dimensions: 171.6 × 68 × 32.5 mm (6.7 × 2.7 × 1.3 in)
  • Weight: 151 g (0.33 lb) excluding batteries
  • Certifications: CE, UKCA
  • Shock: 4 feet drop per EN 61010-1
  • Vibration: Random Vibration per MIL-PRF-28800F Class 2
  • Electromagnetic Compatibility Standards (EMC): EN61326-1