Monitor up to 3 environmental parameters with one tiny instrument: Wind Speed, Air Temperature, Relative Humidity (RH). Light weight, tiny size with simple, one-hand, operation. They are perfect for scientists, agricultural specialist, facilities managers, HVAC professionals, home inspectors, field technicians, health and safety personal, hazmat crews, outdoor enthusiasts, educators, and coaches … all of whom need accurate information to properly access environmental conditions and make crucial decisions. Reads air speed in addition to the wide selection of environmental parameters detailed above. Will sense airflow as low as 0.4 m/s with an accuracy of ±3% (4% >20m/s). Replaceable snap-in anemometer vane is available. Features min/max, hold, a backlight and come complete with a wrist strap, carry pouch, and button cell battery providing at least 40 hours of continuous use. Dimensions: 4.75" × 1.75" × 7/8" (120 × 44 × 21 mm). Weight: 2.2 oz (65 g).