Backlight on or off of GVDA GD155 Digital Anemometer Portable High-Precision Air Volume Tester Wind Speed Meter Handheld Measuring Wind Speed Tools
Press the button 
and hold it for more than 2 seconds to enable or disable the backlight function.
Backlight on or off of GVDA GD155 Digital Anemometer Portable High-Precision Air Volume Tester Wind Speed Meter Handheld Measuring Wind Speed Tools
Temperature unit selection of GVDA Wind speed tester GD155 Digital Anemometer Handheld Wind Speed Meter for Measuring Wind Speed, Temperature and Wind Chill with Backlight LCD
MAX/MIN/AVG function of GVDA High Precision Anemometer GD155 Digital Handheld Anemometer Waterproof Wind Speed Meter Outdoor Measure Windsurfing Tester
