Review Garmin gps

GPSMAP 76 Rugged, waterproof, unsinkable GPS receiver.
Whether you choose the basic navigation features of the GPS 76 or the detailed mapping capabilities of the GPSMAP 76, you will always know where you are and where you're going. It features built-in quadrifilar antennas for superior reception. View your location on a large, sharp, four-level grayscale screen for excellent separation and contrast.

What is GPS http://www.mncgroup.co.uk/gps/info.htm