Garmin Fishfinder 100 Owner's Manual page 8

Introduction
What can the Fishfinder 100
Display?
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The Fishfinder 100 is able to display a variety of useful information
about the underwater environment. Below are a few things the unit will
help you see.
The unit displays water depth and can provide a warning for shallow or
deep-water conditions.
The unit can display the battery voltage that is available to the unit.
If equipped with a capable transducer, the unit can display the water
temperature.
If equipped with a capable transducer or Speed Sensor, the unit can
display the boat's speed over water.
The unit displays fish as arches or fish symbols and can alert you when
a fish is detected.
With GARMIN's See-Thru technology the Fishfinder 100 can display
more than just the thermocline and structure, the unit displays fish in
and below the thermocline, trees, brush and deadfall like you have
never seen before!
Garmin's unique DCG (Depth Control Gain) system provides a clear
graphic representation of the bottom type and its shape.
* requires optional transducer or sensor