Garmin GRF 10 Rudder Feedback Sensor [010-11829-00]GRF 10 Rudder Feedback Sensor Compatible Devices Pair this sensor with the GHP 12 to provide rudder position feedback and to detect and avoid rudder stops while sailing or boating. The GRF 10 uses a magnetic sensor to relay position information, eliminating friction that causes other types of sensors to wear out. The arm of the GRF 10 is connected to the rudder of the boat and relays position information through the sensor to the mariner so they know