WindGuide is compact, convenient, rugged and weather safe making it the perfect portable guide for outdoor enthusiasts of hunting, sailing, wind and kite surfing, archery and many more. Measures up to 65 mph wind speed. Wind chill indicator when temp falls below 32??F. Temperature readings in ??F or ??C. Beaufort wind force scale. Backlight for easy reading, low battery indicator, protective rubber cover, weather resistant. 1" impeller. Includes lanyard and CR2032 battery. 2 year warranty.