Pellor Wireless Indoor Disply Digital Swimming Pool Thermometer SPA Floating Thermometer with Solar 433MHZ wireless receives 3 chanels water temprature. Max/min record of indoor and water temperature. Waterproof and floating Outdoor transmitter. Receiver: 2xAAA 1.5V alkaline batteries.(not include) Transmitter: 1.5V 2xAA alkaline batteries.(not include)