Hand-Held Hygrometer
The MDM25 is a portable, battery-operated hand-held hygrometer, and is available with a number of different probe configurations. It displays relative humidity, temperature and one calculated value, making this hygrometer suitable for a wide range of applications. The user can choose to display either °C or °F.

Product Features

  • Displays %RH and temperature, plus dew-point, absolute humidity and wet bulb temperature
  • Simple to operate
  • Long term stability: ±1% RH over 12 months

MDM25 Probes

Hand-Held Hygrometer

Measurement Units%RH, °C/°F Ta, °C/°F Td, g/m3, °C/°F Tw
Mechanical specification
Ingress ProtectionIP54 - Hygrometer
Hygrometer Housing MaterialMolded polymer housing ABS + rubber surround
Weight300g (10.58oz)
Display ResolutionGraphic LCD 128 x 64 pixels
Electrical output/input
Supply Voltage4.5 V (3 x AA batteries - provide approximately 70 hours of operation)
Electrical ConnectionsM9 5-way triad connector


Measurement Range (RH)0 - 100% RH
Accuracy @ 25°C (77°F) Temperature<±0.2°C (±0.36°F)
Stability - RH Sensor±1% RH/year
Response time - RH Sensor<10 sec typical (for 90% of the step change)
Measurement & Operating range (T)
   Fixed and Standard Probe
   Sword Probe
   Remote Probe

-20 to +80°C
-20 to +100°C
-20 to +150°C
Accuracy @ 25°C Humidity
   Fixed Probe
   Remote Probes

±2% RH (10 - 90% RH)
±2% RH (5 - 95% RH)
Mechanical Specification
Fixed Probe (FPR)30g
Standard Probe (SPR)90g
Sword Probe (SWPR)500g
Round 300mm Probe (HTPR300)  380g
Round 500mm Probe (HTPR500)620g

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