The REED R4100 is a rotating-vane thermo-anemometer that measures air velocity across a wide range of units (fpm, m/s, km/h, mph, knots, Beaufort) while simultaneously showing air temperature on its dual LCD. Beyond raw velocity, it calculates air volume in CFM or CMM, making it useful for HVAC balancing, duct testing, and filter-blockage checks. It includes data hold and min/max/average logging, an internal memory for storing readings, and mounts to a tripod for hands-free measurement.