NO LONGER AVAILABLE - USE GR16 GPS -- SORRY BOTH OF THESE ARE NOW NO LONGER AVAILABLE, NOR DO WE HAVE ANY FURTHER SUBSTITUTE PART NUMBERS--------------------------------------------------------------------------------------------AS GR50GPS ReceiverThe Humminbird 50-Channel GPS/WAAS receiver gives you lightning fast position fixes accurate within 2.5 meters. This receiver can be used in lower signal areas (compared to a AS GR16) and still maintain a position fix. It also has a faster Time to First Fix (TTFF). The receiver's dimensions are: 3.25" diameter, 1.5" high and comes with 20 feet of cable and has a 1"-14 thread count stem mountable with optional antenna stem (antenna stem not included).For Use with1155c1157c1197c SI718728768778C788C798C SI858c898c SI917C947C955c957c958c967C 3D997c SI998c SIPart # 407480-1