The host is placed indoors to display time, temperature, humidity, and other data. The transmitter is placed in an outdoor pool to collect data and transmit it to the host. Suitable for various indoor and outdoor situations. It can be used in swimming pools, spas, aquariums, fish ponds, etc. The outdoor sensor transmits data at a distance of 60 meters. Improved and optimized sealing ensures no leaks and defects. Time display: 12/24h optional. The real-time temperature of the water area where the sensor is located and the real-time indoor temperature of the host can be displayed on the same screen. Supports the maximum and minimum temperature readings of the day. Indoor and outdoor temperature display: °C/°F optional. Host indoor temperature detection range: -9.9°C to +50°C (14.2°F to 122°F). Pool sensor temperature detection range: -40°C to +70°C (-40°F to 158°F). Temperature error range: ±1°C, transmission range: 60 meters. It's a very convenient way to know the temperature of your pool. Once installed, simply check the display to instantly know the water temperature without having to take your feet out of the pool, remove the thermometer, put your hands in, etc. Power supply: Inner sensor: 2 x 1.5V AAA alkaline batteries (not included) Outer sensor: 2 x 1.5V AAA alkaline batteries (not included)