Extech-5-in-1-Environment-Tester-Hygro-Thermo-Anemometer-Light-Sound-Meter-EXTECH-EN300-The-Extech-EN300-5-in-1-environment-tester-measures-humidity-temperature-air-velocity-light-&-sound-in-one-compact-h&-held-unit-Its-large-dual-LCD-simultaneously-displays-temperature-&-air-velocity-or-relative-humidity-As-the-meter-has-sensors-top-&-bottom-the-characters-on-display-reverse-direction-depending-on-mode-hygro-thermo-anemometer-or-light-sound-A-built-in-low-friction-vane-wheel