The unit measures air velocity in five user-selectable values: meters per second, feet per second, miles per hour, kilometers per hour, and knots. It also displays: maximum airflow measured, temperature in degrees F and C, and wind chill temperature in degrees F and C. Measurements are fast with reading updates two times per second. Simple one-button operation eliminates the need to refer to directions. Plastic housing and water-resistant design keeps out moisture, dust and dirt, assuring a long life. High contrast LCD digits are over 3/8-inch-high and easy to read. Electro luminescent backlight allows the display to be read in total darkness. To assure accuracy an individually serial-numbered certificate is provided from an ISO 17025 calibration laboratory accredited by A2LA. It indicates traceability to standards provided by NIST (National Institute of Standards and Technology). Supplied with lanyard, nylon carry case and long-life lithium battery.