• Usually ships in 13-14 weeks



  • Precision relative humidity and temperature calibrator
  • Measuring ranges:
    • Temp: 50 to 122°F (10 to 50°C)
    • RH: 10 to 90%
  • Accuracy:
    • Temp: ±0.1°C (±0.18°F)
    • RH: ≤ ±1% RH (10-70% RH)
    • RH: ≤ ±1.5% RH (70-90% RH)
  • Calibrate up to 5 sensors, or more
  • Integral chilled mirror reference hygrometer
  • UKAS accredited calibration, as standard
  • On-site calibrations
  • Chamber volume: 122.1in³ (2000 cm³)
  • Chamber dimensions: 4.13x4.13x6.3in 105x105x160mm)


Michell Instruments Opti-Cal Humidity & Temperature Calibrator comprises a humidity and temperature controlled chamber that can house up to five or more humidity sensors, depending on their physical dimensions. The humidity and temperature within the chamber are closed-loop controlled and continuously monitored by a precision chilled mirror reference hygrometer.

The Opti-Cal works by time proportioning the flows of dry and saturated air according to the pre-selected relative humidity value. The chamber temperature is controlled by a four-zone Peltier heat pump arrangement for maximum stability and minimum temperature gradient. The saturator assembly can be filled easily with the distilled water reservoir at the front of the unit and the easily accessible desiccator can be re-charged by heating when required. No other maintenance is necessary. The only external service required is a single phase power supply.