Originally Posted by giddyup
If that is the hole on the back next to the socket for the tranducer cable, the one I bought recently from Seamark Nunn has a rubber cover that fits over the aerial socket. Maybe that is how Garmin solved the problem on the latest versions.
Thanks Two Stroke!
Yes indeed, Garmin are now shipping rubber covers - but beware these can trap water inside.
The units are a great piece of kit, but they have slipped up slightly by having both internal and external antenna options in one model. Garmin are, as far as I have been able to tell not admitting to a design fault (yet).
If you are buying one of these I would suggest you make sure the rubber cover is included, not so much for the unit's protection but to reinforce the point to the supplier.