Seriously, this must be a Golden Age for our species. We may have touched the moon, but a wrist-based fish finder will be what aliens will talk about when they land here 100 years from now—post nuclear and environmental holocaust, naturally.
You just dip the green sensor into the murky deep and watch as pixelated fish wriggle across your wrist. I was seriously fascinated by fish finders when I was a kid. I was convinced you could use them to see through solid earth. Anyway, this looks about right for dear old Dad this holiday.