This Garmin 8-pin transducer to 6-pin sounder adapter cable (010-11612-00) allows you to connect newer 8-pin transducers to devices that require a 6-pin connector.
Compatible with:
-  GPSMAP 421s, 441s, 521s, 546s, 720s, 740s
- GSD 22
For complete list of compatible units and transducers, click here