Can measure indoor and outdoor temperature and humidity. 433MHz transmitting frequency, you can know outdoor temperature and humidity with indoor receiver. Outdoor(CH 1,2,3) and indoor temperature/humidity HI/LOW alarm. C / F temperature unit selectable. Min/Max records of temperature and humidity. Temperature and humidity manual calibration. Temperature and humidity indication. Comfort level indication. Can receive up to 8 sensors. With dip switch to set up and fix 1-8 channels. Long searching function after communication is lost. Free standing or hanging. Display: LCD Indoor Temperature Measurement: 0~60C / 32~140F Outdoor Temperature Measurement: -40~60C / -40~140F Temperature Accuracy: 1C Humidity Measurement: 10%-99% Humidity Accuracy: 5% Transmission Range: 100 meters(300 feet) in open area Transmission Interval: 60 seconds Remote Sensor Battery: 2 * 1.5V AAA Batteries(NOT included) Receiver Battery: 4 * 1.5V AAA Batteries(NOT included) IP Grade: IP44 Remote Sensor Size(1pc): 45 * 110 * 21mm / 1.77 * 4.33 * 0.83in Receiver Size: 115 * 125 * 24mm / 4.53 * 4.92 * 0.94in Remote Sensor Weight(1pc): 50g / 1.76oz Receiver Weight: 145g / 5.13oz Note:Please don't soak the outdoor transmitter into the water. colour:Gray + black Material:ABS plastic Package Contents: 1 * Wireless thermometer and hygrometer 4 * transmitter 1 * User Manual (English) Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.