The Extech MO55 is a versatile moisture meter designed for wood and other building materials, combining two testing methods in one tool: a traditional pin-type mode for accurate internal moisture readings and a pinless, non-invasive mode for fast surface scanning. This dual functionality makes it especially effective for detecting, confirming, and diagnosing moisture problems in construction, restoration, and inspection applications, where both speed and accuracy are important.
The Extech MO55 is a versatile moisture meter designed for wood and other building materials, combining two testing methods in one tool: a traditional pin-type mode for accurate internal moisture readings and a pinless, non-invasive mode for fast surface scanning. This dual functionality makes it especially effective for detecting, confirming, and diagnosing moisture problems in construction, restoration, and inspection applications, where both speed and accuracy are important.
Dual measurement capability means you can switch between pin and pinless modes, allowing for both non-destructive scanning and precise verification. Pin mode, best for accurate internal moisture measurement, uses two metal pins inserted into the material to measure electrical resistance and then converts this into a moisture percentage reading. Pinless mode (non-invasive) uses an electromagnetic sensor to scan beneath the surface (measures up to about 1" (25 mm) deep) without damaging the material and is ideal for quick scanning of large areas.
Features
Applications
| Display | Backlit Color LCD |
| Display | Backlit Color LCD |
| Sensor Type | Replaceable threaded contact pins, 0.3" (8 mm) non-penetrating electromagnetic sensor pad |
| Sensor Type | Replaceable threaded contact pins, 0.3" (8 mm); non-penetrating electromagnetic sensor pad |
| Electrode Pin Length | 0.3" (8 mm) |
| Electrode Pin Length | 0.3" (8 mm) |
| Electrode Pins | Integrated, Replaceable, 0.3" (8 mm) |
| Electrode Pins | Integrated, Replaceable, 0.3" (8 mm) |
| Measurement Principle | Electrical resistance (pins) Capacitance (pinless) |
| Measurement Principle | Electrical resistance (pins); Capacitance (pinless) |
| Measurement Depth | Pinless < 1" (25 mm) |
| Measurement Depth | Pinless < 1" (25 mm) |
| Auto Calibration | Pinless mode in open air |
| Auto Calibration | Pinless mode in open air |
| Measurement Indication | Digital, Moisture Droplet icons and Beeper for High, Medium, Low indication |
| 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% |
| 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 (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% |
| 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 (72 to 77°F) at (22 to 25°C) |
| 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% |
| 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 1" (25 mm) deep varies with material under test |
| 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 varies 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% |
| 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% |
| Relative Moisture Content Max Resolution (Pinless) | 0.1% |
| Auto Power Off | After approx. 3 minutes. |
| Auto Power Off | After approximately 3 minutes |
| Battery Type | 3 × 1.5 V, AAA batteries |
| Battery Type | 3 x 1.5 V, AAA batteries |
| Power Consumption | Operating Current: < 15 mA (Average), APO < 10 µA |
| 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 |
| 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 | 41 to 113°F (5 to 45°C); < 80% RH |
| Operating Conditions | 41 to 113°F (5 to 45°C) < 80% RH |
| Storage Conditions | 32 to 122°F (0 to 50°C); < 85% RH |
| Storage Conditions | 32 to 122°F (0 to 50°C) < 85% RH |
| Operating Altitude | 6562' (2000 m) |
| Operating Altitude | 6562' (2000 m) |
| Dimensions | 6.7 × 2.7 × 1.3" (171.6 × 68 × 32.5 mm) |
| Dimensions | 6.7 x 2.7 x 1.3" (171.6 x 68 x 32.5 mm) |
| Weight | 0.33 lbs (151 g) excluding batteries |
| Weight | 0.33 lbs (151 g) excluding batteries |
| Certifications | CE, UKCA |
| Certifications | CE, UKCA |
| Shock | 4 feet drop per EN 61010-1 |
| Shock | 4' (1.22 m) drop per EN 61010-1 |
| Vibration | Random Vibration per MIL-PRF-28800F Class 2 |
| Vibration | Random Vibration per MIL-PRF-28800F Class 2 |
| Electromagnetic Compatibility Standards (EMC) | EN61326-1 |
| Electromagnetic Compatibility Standards (EMC) | EN61326-1 |
| Accessories Included | Protective cap, 3 × AAA batteries, 2 × replacement pins, quick start guide |
| Accessories Included | Protective cap, 3 x AAA batteries, 2 x replacement pins, quick start guide |
| Warranty | 2 years |
| Warranty | 2 years |
| Display | Backlit Color LCD |
| Display | Backlit Color LCD |
| Sensor Type | Replaceable threaded contact pins, 0.3" (8 mm) non-penetrating electromagnetic sensor pad |
| Sensor Type | Replaceable threaded contact pins, 0.3" (8 mm); non-penetrating electromagnetic sensor pad |
| Electrode Pin Length | 0.3" (8 mm) |
| Electrode Pin Length | 0.3" (8 mm) |
| Electrode Pins | Integrated, Replaceable, 0.3" (8 mm) |
| Electrode Pins | Integrated, Replaceable, 0.3" (8 mm) |
| Measurement Principle | Electrical resistance (pins) Capacitance (pinless) |
| Measurement Principle | Electrical resistance (pins); Capacitance (pinless) |
| Measurement Depth | Pinless < 1" (25 mm) |
| Measurement Depth | Pinless < 1" (25 mm) |
| Auto Calibration | Pinless mode in open air |
| Auto Calibration | Pinless mode in open air |
| Measurement Indication | Digital, Moisture Droplet icons and Beeper for High, Medium, Low indication |
| 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% |
| 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 (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% |
| 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 (72 to 77°F) at (22 to 25°C) |
| 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% |
| 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 1" (25 mm) deep varies with material under test |
| 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 varies 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% |
| 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% |
| Relative Moisture Content Max Resolution (Pinless) | 0.1% |
| Auto Power Off | After approx. 3 minutes. |
| Auto Power Off | After approximately 3 minutes |
| Battery Type | 3 × 1.5 V, AAA batteries |
| Battery Type | 3 x 1.5 V, AAA batteries |
| Power Consumption | Operating Current: < 15 mA (Average), APO < 10 µA |
| 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 |
| 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 | 41 to 113°F (5 to 45°C); < 80% RH |
| Operating Conditions | 41 to 113°F (5 to 45°C) < 80% RH |
| Storage Conditions | 32 to 122°F (0 to 50°C); < 85% RH |
| Storage Conditions | 32 to 122°F (0 to 50°C) < 85% RH |
| Operating Altitude | 6562' (2000 m) |
| Operating Altitude | 6562' (2000 m) |
| Dimensions | 6.7 × 2.7 × 1.3" (171.6 × 68 × 32.5 mm) |
| Dimensions | 6.7 x 2.7 x 1.3" (171.6 x 68 x 32.5 mm) |
| Weight | 0.33 lbs (151 g) excluding batteries |
| Weight | 0.33 lbs (151 g) excluding batteries |
| Certifications | CE, UKCA |
| Certifications | CE, UKCA |
| Shock | 4 feet drop per EN 61010-1 |
| Shock | 4' (1.22 m) drop per EN 61010-1 |
| Vibration | Random Vibration per MIL-PRF-28800F Class 2 |
| Vibration | Random Vibration per MIL-PRF-28800F Class 2 |
| Electromagnetic Compatibility Standards (EMC) | EN61326-1 |
| Electromagnetic Compatibility Standards (EMC) | EN61326-1 |
| Accessories Included | Protective cap, 3 × AAA batteries, 2 × replacement pins, quick start guide |
| Accessories Included | Protective cap, 3 x AAA batteries, 2 x replacement pins, quick start guide |
| Warranty | 2 years |
| Warranty | 2 years |
