321 Digital Thermo-Hygrometer adopts large LCD display, has temperature and humidity measurement function. The accuracy is ±3.5%RH (at 25℃, 5%~95%RH), ±2.5℃ (at 25℃).
The 321 Humidity & Temperature Meter is a compact handheld device featuring a large 3‑1/2" digital LCD display with backlight and automatic polarity indication. It uses a precision capacitance sensor for humidity and a thermistor probe plus a type K thermocouple for temperature measurement.
The meter provides a sampling rate of 2.5 samples per second, auto power‑off after about 15 minutes of inactivity, and operates on a standard 9 V battery. It is rated for operating temperatures from 32 °F to 122 °F and humidity up to 80 %RH non‑condensing.
| Display | Large 3‑1/2 digital LCD with backlight |
|---|---|
| Humidity Sensor Type | Precision capacitance sensor |
| Temperature Sensor Type | Thermistor probe and type K thermocouple |
| Response Time | 3 minutes |
| Sampling Rate | 2.5 samples per second |
| Power Supply | One standard 9 V NEDA 1604 or 6F22 battery |
| Dimensions / Weight | 225 × 45 × 34 mm / 200 g |
| Humidity Measurement Range | 0 % – 100 % RH |
| Temperature Measurement Range | -20 °C to +60 °C (‑4 °F to 140 °F) |
| Resolution | 0.1 %RH, 0.1 °C/°F |
| Humidity Accuracy | ±3.5 %RH (5 %–95 % RH) |
| Air Temperature Accuracy | ±2.5 °C / ±3.5 °F |
| Auto Power‑Off | Shuts down after ~15 min of inactivity |
It uses one standard 9 V NEDA 1604 or 6F22 battery.
The meter automatically shuts down after about 15 minutes of inactivity.
It measures temperature from –20 °C to +60 °C (‑4 °F to 140 °F).
The humidity range is 0 % to 100 % RH.