Dropped this unit into the saltwater at high tide and had to wait 6 hours to pull it out, and IT WAS STILL ON even though it had eventually taken on water.  The unit lasted another 6 months of use in regular splashed environments before the long stay in saltwater finally got to it.  I immediately went out and bought another one.  Can purchase data on all bouy markers in your area and other data on CD for loading via PC connection.  Holds a ton of waypoints.  Quick to find itself after power off (have several other makes and models and this is the fastest).  Would recommend Garmin products to anyone.  In addition to being heavily capable against all weather conditions, the unit is also built to withstand dropping, etc.  The maps it comes with are adequate for normal use on highways etc without buying the CD additions, and are of recent vintage.  Nearby highway just recently completed was included in the standard onboard map.