Furuno SCX21 Satellite Compass - NMEA 0183 [SCX21]SCX21 Satellite Compass Utilizing four separate GNSS Antennas for the ultimate in responsiveness, the SCX21 sets a new standard for reliable and accurate heading for all of your marine electronics. The four antennas ensure reliable heading performance, even under the most challenging of conditions. The unprecedented quad antenna design of the SCX21 makes it capable of calculating extremely accurate heading, pitch, roll, and heave information, even