The Garmin Echomap Plus 62cv chart chartplotter with the GT20 transducer  is a combined device with a bright six-inch anti-glare display designed for fishing and navigation, supports the modern sonar Garmin CHIRP and the scanning sonar CHIRP ClearVü, built-in cartography and wireless communications. Allows you to exchange routes with other Echomap or Striker devices and create your own maps.
Also has a free application ActiveCaptain, which allows you to access OnеChart for downloading new maps, and to the ActiveCaptain community for information on berths and other objects. 
Advantages of Garmin Echomap Plus 62cv:

6-inch color anti-glare display

clear images of the scanning sonar

support for BlueChart cartography

function SailAssist

Garmin CHIRP support

Quickdraw Contours for creating your own maps

microSD

Specifications:

Radiation power	500W
Maximum depth	580 m
Food	12 V
Water resistant	IPX7
Dimensions	21.8 x 13.0 x 6.2 cm
Weight	680 g