Flow Meter measures in mph, km/h, knots, m/s, fps and cm/s. Backlit display shows instant speed reading and temperature, plus minimum, maximum and average (in 3-second to 24-hour increments) measurements. Operating temperature: –20° to 70°C. Meter includes the display unit, water impeller, telescoping rod (3.9'–6.6') and carrying case. Runs on two AA batteries, sold separately.