Ambient Weather WS-18 Wireless 8-Channel Floating Pool and Spa Thermometer with Remote Thermo-Hygrometer Finally, an easy way to read your water temperature from both indoors and outdoors. The WS-18 wireless pool and spa thermometer is water proof and floats on the surface of the water. The sensor displays and wirelessly transmits the water temperature to the display console. The 8-channel selectable switch allows you to monitor water temperature from up to eight different locations. The screw-on lid design with internal gasket provides a leak free, water resistant design. Each remote sensor includes dip switches for channel selection and units of measure (degF vs degC).