Used 19 pin Connector Data Cable For Garmin GPSMAP 520, 521, 525, 526, 530, 531, 535, 536, 540, 541, 545, 546, Fishfinder 400C - AliExpress
VENDESI GARMIN GPSMAP 521S
User manual for Garmin GPSMAP 521 - a user manual, servicing manual, settings and specifications ofGarmin GPSMAP 521 - User manuals and advice for your devices - User-Manual.info