The powerful GSD 22 digital sounder adds detailed sonar data to your compatible Garmin chartplotter over the Garmin Marine Network.This black-box sounder connects to your chartplotter over the Garmin Marine network to provide high-speed data returns and super-crisp detail. Once connected, any plotter on the network can view the 22's detailed sonar data and overlay it on the map page. You can also use the GSD 22 with Garmin's CANet™ to connect to non-network chartplotters. See list of compatible units in 'more details'