The CFM Anemometer reads air velocity in m/s, km/h, mile/h, knots or ft/min and air volume in CFM or CMM plus temperature in °C or °F. It is excellent for HVAC work. This anemometer also features min-max, hold and an RS232 computer interface. Data Lab graphical software can be used with this instrument. The detachable probe is easy to repair or replace. Each unit includes a hard carrying case, probe and 9V battery.