This app is a wireless fishfinder app "Tankenmaru SMART". (free)
With fishfinder, you can detect the topography of a school of fish and the bottom of the water and check the situation.
It can be used on fishing boats equipped with the app-compatible finder-maru master unit and Tankenmaru SMART FISH FINDER.
The finder circle is an epoch-making system that can wirelessly catch the fish finder image from the parent machine fish finder and watch the fish finder image at hand.

■ Information on ships equipped with the app-compatible search round master machine ・ ・ ・ http://fishing.shimano.co.jp/fishing_info/tanken_shipinfo/kanto.html

[Main functions]
■ Fishfinder function
・ Display of water depth
・ You can see the bottom of the water and the position of the fish at a glance.
・ Accufish (You can see the size of the fish) However, the master unit is limited to products that support Accufish.
・ Fish school notification (alarm / vibration)
■ Fishfinder screen save (video / still image)
■ Camera function
■ Number counter function
* There is no wireless communication function with the electric reel.
http://fishing.shimano.co.jp/tool/tankenmaru_smart/index.html