ERAY Digital Psychrometer Hygrometer Thermometer, Temperature and Humidity Meter Gauge Monitor Indoor Handheld with Dew Point and Wet Bulb Temperature, Battery Included 2-IN-1: It is designed to combine the functions of humidity meter, temperature meter, wet bulb temperature and dew point temperature. And Dew point is a measure of how much water vapor actually in the air. BACKLIGHT LCD DISPLY: With a bulb to light up the LCD screen, it is easy to read the measurements in the darkness. LCD brighter in the darker places. DUAL DISPLAY: Temperature range: -30 C~60 C (-22 F~140 F); Humidity range: 0~100%RH; Dew point temperature range: -50 C~60 C (-58 F~140 F); Wet bulb temperature range: -50 C~60 C (-58 F~140 F) MULTIFUNCTIONAL: Unit and mode conversion (C, F, dewpoint and wet bulb), Max Hold and Min Hold Function; Auto shutdown without operation after 15 minutes; 6F22 9V Battery included. WIDELY USED: Used for HVAC, industry, agriculture, meteorology, medical, daily life, building engineer, paranormal investigator, in wine cellar, machine room, data storeroom and etc. If you have any questions, just tell us. We will willingly bear all the responsibility, send you a replacement or offer you a full refund. Display: Large 4 1/2 dual digital LCD display Temperature Measurement Range: -30 C~60 C (-22 F~140 F) Humidity Measurement Range: 0~100%RH Dewpoint Temperature: -50 C~60 C (-58 F~140 F) Wet Bulb Temperature: -20 C~60 C (-4 F~140 F) Temperature Accuracy: 0.5C/0.9F (10~55C); 1.5C/3F (all other ranges) Humidity Accuracy: 3%RH (at 25C, 10%~90%RH); 4.5%RH (At other ranges) Resolution: 0.1%RH, 0.1C/0.1F Response Time: 10S Auto Shutdown Time: 15 minutes Battery: 6F22 9V battery (Included) Working Environment: -20C~60C Storage Environment: -20C~60C; &lt; 80% RH non-condensing Dimensions: Approx. 6.7x2.2x1.4 in / 170x55x35 mm Net Weight: Approx.143 g 45%RH-75%RH: Temperature at 15C~25C, the suitable environment fit for the human body 40%RH-70%RH: Room environment 40%RH-60%RH: Library, gallery and museum 45%RH-60%RH: Computer room and communication room 40%RH-60%RH: Agricultural materials and cotton fabrics storage 50%RH-60%RH: Dairy storage 60%RH-70%RH: Fruits storage 30%RH-50%RH: Help to prevent from the disease, treatment environment 1 x Temperature Humidity Meter 1 x 9V Battery 1 x User Manual It is ideal for home, apartment, industrial, agriculture, laboratory, greenhouse, warehouse, restaurant, wine cellar, aquaculture and etc. In one&#039;s element, ensure whether you and your family were in a good environment. In one&#039;s element, the vegetables, fruit and plants will get more efficient growth. In one&#039;s element, the goods in the warehouse will be stored longer and better. In one&#039;s element, the wine will be stored better and don&#039;t worry about the wine going bad. In one&#039;s element, ensure a comfortable environment in your house when you are warming yourself. In one&#039;s element, the vegetables, fruit and food will be stored better.