Widely Used: Designed for use in the swimming pool, heated pool, wood fired tubs, spa thermometer, monitor the temperatures in a koi pond, monitor the temperature in outside hot tub from inside the house. Multi-function: Snooze function Alarm; Adjustable calendar; Radio controlled time. Measure Range: Outdoor temperature range: -40F~140F-40C ~ 60C; Indoor temperature range: 32F~122F0C~50C Easy to Use: You can read the water temperature from both indoors and outdoors. Check outdoor temperature of the swimming pool water even when you in the living room. Material: Made of ABS, has high stability and good waterproof performance. Solar power with Digital LCD Display. Easy to see the data. Note: 1. Please use a good alkaline battery, do not use rechargeable battery. 2. Please install outdoor transmitter (sensor) power supply first, and then install indoor receiver (display) power supply.