Water Speed Sensor (4-Pin) f/echo™ Series FishfindersEasily collect speed data and send it to your echo™ fishfinder with our water sensor.Simply mount our speed sensor on the transom of your vessel and connect it to your device. The paddle wheel on the speed sensor turns as the vessel moves through the water, and speed data is collected and displayed on your device.WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.