The Humminbird SmartCast RF40A Remote Sonar Sensor is a vintage transducer designed specifically for fishing activities. This green sensor, made by the reputable brand Humminbird, offers remote sonar technology to help anglers locate fish more effectively. The SmartCast technology ensures accurate and reliable readings, making it a valuable tool for any fishing enthusiast looking to enhance their fishing experience. Replacement  for sensor that originally came with your smartcast. New old stock.