Ambient Weather WS-20 Wireless 8-Channel Floating Pool and Spa Thermometer with Outdoor Remote Thermometer Finally, an easy way to read your water temperature from both indoors and outdoors. The WS-20 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. Also includes an indoor/outdoor thermometer for monitoring air temerature. 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.