Summary: I needed a replacement for my 3 year old Garmin 90 which eventually failed due to saltwater corrosion of the 6 pin power lead which connected to the Fishfinder unit. I wanted the following features if possible: 1. 200khz for good definition in shallower waters 2. Watertight connections into the fishfinder 3. Greyscale display of at least 8 shades 4.