Garmin GPSMAP 421s 4-Inch Waterproof Marine GPS and Chartplotter with Sounder

The GPSMAP 421S, by Garmin is a solid chartplotter. It's highlight is the 4" QVGA 240 x 320 pixel color screen delivering ultra bright (over 800 nits) digital,  views with an improved high-speed delivery. The high speeds of panning and map drawing are the result of an improved digital design.

The GPSMAP 421S is preloaded with Garmin's marine worldwide basemap, satellite-enhanced with an easy-to-use interface design that goes a long way to help you easily navigate the open waters.

It also interfaces, via the SD Slot, with (optional) BlueChart g2 Vision cards which add functionality and have added features such as high-resolution satellite imagery, 3D views and Auto technology.

The GPSMAP 421S is also capable is receiving U.S. graphical weather data via the optional Garmin GXM 51 Weather and Audio XM Satellite Receiver