Features:1) It can receive the signal of three sensor units, and display them on thescreen, the distance about 30m in the open field2) Measure the indoor temperature and humidity3) Measure range: -10 ~ 60°C or 14 ~ 140°F; 20%RH ~ 80%RH4) Accuracy: ±1°C or ±2F, ±5%RH5) Display date, time and time alarm6) Max./min. indoor temperature and humidity memory7) Back light8) Weather prediction9) Celsius and Fahrenheit switchSpecifications:1) Size of the product: 142 x 80 x 31mm2) Screen size: 53 x 44mm3) Eight keys: ADD, code, C/F, max./min., SUB/CLR, alarm, clock, light4) Three LR6 AM3 AA/1.5V alkaline batteries5) Light color: greenAccessory unit (sensor):1) They can send the signal to the main unit2) Measure the outdoor temperature:a) Measure range: -20 ~ 70°C or -4 ~ 148°Fb) Accuracy: ±1°C or ±2°F3) Max./min. outdoor temperature memory4) Celsius and Fahrenheit switch5) Waterproof6) It can be hanged on the wall or put on the tableSpecifications:1) Size of the product: 95 x 62 x 23mm2) Screen size: 25 x 12mm3) Three keys: code, C/F, max./min.4) Two LR03 AM4 AAA / 1.5V alkaline batteries