LIVEV? DOWN: Provides real-time moving sonar images. You can see fish swimming toward or away from the boat. You can see small baitfish and large target fish swimming around even your lure.
REALV? 3-D DOWN: Allows your boat to be stationary and still see things in 3-D around your boat. It shows history of only 1 sweep.
REALV? 3-D HISTORICAL: Used for finding fish while your boat is moving. This shows the entire water column you have passed over in 3-D from the bottom of the surface and all of the fish in between.