I had a Sena 50S when I started this Black Hills trip. After day one's torrential downpour it quit working. From past experiene we always travel with backup headsets, so used a S20 for the rest of the trip.
Now that I've contacted Sena for my 50S about the failure, they've informed me they are not waterproof and should only be used in light rain.

I replied to that email and waiting for my next communication from them.
As a user of most major models of the Zumo over the last 15 years, I can say it is actually daylight readable, not just a claim, this time it's true. The XT is the Zumo we've all been waiting for but was never delivered. It answers most of my complaints that have built over the years. No more being unable to know where the hell you are because you zoomed out just a tiny amount. You see the small roads now.