Davis Wind Scribe Ultrasonic Wind Meter

Ultrasonic wind meter uses technology to read current wind speed, highest positive speed (headwind), lowest negative speed (tailwind), 5-second average, and running average.
Select from mph, km/h, fpm, m/s, f/s, or knots, plus temperature and wind chill in tenths of °F or °C.
Sensitive to breezes as low as 0.4 mph, yet withstands winds as high as 150 mph.
Includes replaceable 3-volt lithium battery, lanyard and mounting bracket.
Battery lasts up to 600 hours.

Dimensions: 5" x 3" x ¾" (12.7 x 7.6 x 1.9 cm)
Weight: 3½ oz (100 grams).