TRSI TA640A Handheld High Precision Wind Speed Instrument Wind Volume Tester Features: 1. 8-blade design, with low-friction high-precision bearings, more responsive 2. Can lock the maximum, minimum and real-time values ??during the measurement process 3. High-definition large screen display with white background light 4. Use 2x1.5VAAA (not included) No. 7 batteries, automatically shut down after 15 minutes of no operation (can be canceled manually) Parameters: 1. Measuring range: 0.1-30.0ms 2. Resolution: 0.1ms 3. Temperature measurement range: 0-45 degrees Celsius 4. Wind speed display: four-digit display, up to 9999 5. Sensor: infrared laser tube cutting method 6. Sampling rate: 2 timessecond 7. Automatic shutdown: 15 minutes (can be turned off manually) 8. Power supply: 2 x 1.5V AAA (RO3LRO3) (not included) 9. Operating environment: -10-50 degrees Celsius, relative humidity within 80%, indoor altitude less than 2000m 10. Storage environment: -10-50 degrees Celsius, relative humidity within 70% (remove the battery) 11. Overall size: 168x59x29mm 12. Weight: about 120g (without battery)