We have been hearing some great comments lately about how the AIS
The GX2100 does have its own very small AIS display but if you get the chance to see the WatchMate working alongside it as a dedicated AIS collision avoidance system you will immediately understand why people want to combine the products. The WatchMate increases the number of targets you can view and being a dedicated AIS system managing things like alarms, filtering out low priority targets and setting up profiles relevant for your location (ie Anchored, Harbor, Coastal, Offshore) is very very simple to achieve.
Connecting the two devices together is also straight forward, as can be seen here. The power consumption of the WatchMate is so low (1.2watts) it can be left on without being a major drain on you batteries.