Lowrance Hook-7 Base Sonar/GPS Mid/High/Downscan Fishfinder Lowrance Hook-7 Base Sonar/GPS Mid/High/Downscan Fishfinder CHIRP sonar plus downscan imaging the power of today's leading fish finder technologies combined to provide the best possible view beneath boat Highly accurate, built-in GPS antenna plus detailed U.S. Map featuring more than 3,000 lakes, rivers & costal contours to 1,000ft Optional Americas chart upgrades include Lake insight & nautic insight Pro & HD, navionics hotmaps premium & fishing hotspots Pro Global chart upgrade options include navionics+ & jeppesen c-map max-n