Yamaha - Siren Marine External GPS Antenna for Siren 3 Pro - SM-ACC3-GPSA - 6X8-85B81-00-00 Features: Always know where your boat is with enhanced tracking capabilities for your Siren 3 Pro When you remotely mount the External GPS Antenna, the Siren 3 Pro will override the use of the internal GPS antenna, giving you maximum situational awareness anytime, anywhere! Compatible with the Siren 3 pro. M.P.N: SM-ACC3-GPSA 6X8-85B81-00-00 - External GPS Antenna