The Humminbird 678c HD XD is a unit that offers only fish finding features, and does not support any navigational features. However, it’s an extreme depth fish finder (that’s what XD stands for), with a depth capability of 3,000 ft.
The head unit of the 678c HD XD is similar to the other fish finders from the 600 series, featuring a full color, 5-inch diagonal screen, 480H x 640V pixel resolution, with backlight, providing high-definition images, easy to read even in extreme sunlight.
The main sonar of the 678c HD XD is DualBeam Plus, which allows you to scan the water in two modes, with a narrow 20° / 200 kHz beam, for high-accuracy returns, or with a wider beam for a larger coverage, of 60° / 83 kHz.
The XD sonar operates at 50 kHz, with a coverage of 74°. SwitchFire view and split-screen mode are also included. However, this unit does not support sonar recording and does not have screen snapshot options, but there is the possibility of image freeze.
This unit has a power output of 1,000 Watts (RMS), 8,000 Watts (PTP). The standard transducer for this unit is the Transom XNT 9 DB 74 T.
The list of fish finding capabilities of this unit also includes temperature measuring, temperature alarm, and the selective Fish ID+ view.