Ambient Weather WS-PFT120 Wireless Pool and Spa Sensor for WS-PF11 The WS-PFT120 is an additional sensor for the Ambient Weather WS-PF11 Wireless Pool and Spa Thermometer. The WS-PFT120 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 three channel selectable switch allows you to monitor water temperature from three different locations. The screw-on lid design with internal gasket provides a leak free, water resistant design.