High AccuracyWind speed range:0.001~100mph(accuracy:+/-3%+0.2rdg),0.001~45m/s(accuracy:+/-3%+0.1rdg); Temperature range:32~113;resolution:0.001mph.Measure wind speed in MAX/MIN/current.Display in 5 units:m/s,km/h,ft/min,knots,mph. Multi-Function Air Flow Meter1.69x2.3 inch large screen with backlight for easy reading, low power indicator remind you to replace battery in time. Data hold, / switch, extendable and adjustable blades, a better weather monitor for windsurfing, sailing, flying and shooting. Air Flow CFM MeterThe BT-846A wind speed gauge measures wind flow range:0-999900 CFM,resolution:0.001-100,air flow area:0.001-9999 sq.ft.You can simply set the cross section of the damper or vent, the air volume will display in CFM/CMM synchronously during air flow measurement. Separate Extendable Wind SensorBuilt with a paddle of Expandable and user-friendly wind sensor, so you can always watch the readings easily while you test balancing the air conditioning or dust collection system. A large 1.69x2.36 inch backlit LCD display can help you read wind changes easily. Battery SavingLow battery indication and auto/manual power off for p extend the battery using time.(Battery is included) comes with 2 years warranty and lifetime technical support, if you have any problem, please feel free to contact us.