ConPus? BNC Marine Fish Boat GPS Antenna for Garmin GPSMAP-541 GPSMAP- 545S GPSMAP-546 GP-AC14 Amplified (active) GPS antenna to enhance and improve GPS signal reception. Built-in magnets for mounting on car rooftops or other metallic surfaces. Gain=28dB,RHCP,Z=50R, Center Frequency 1575.42MHz3MHz Threaded holes for mounting on aircraft fuselage, boat surfaces or car/RV/SUV vehicle surfaces. Length: 8 m (26 feet)