Extech 250W BLUETOOTH® Connected Environmental Meters include five meters that are compatible with the ExView Mobile App: the AN250W Anemometer, LT250W Light Meter, SL250W Sound Level Meter, RH250W Hygro-thermometer, and the RPM250W Laser Tachometer. Connect up to eight meters (of any combination) to measure and trend various parameters to help accurately diagnose environmental conditions and rotating equipment. These devices operate within a 0 to +40°C temperature range with a transmission distance of >10m up to 90m (within line of sight).