I wanted an inexpensive digital watch for coastal/offshore sailing, with a tidal display. I have a bigger Tidal Watch by Timex, but wanted something that I could wear 24x7 while sailing. This one meets the bill. It is small, but the display is easy to read. The four programming buttons are standard for Casio, and the watch has the usual functions - time/day/date, alarm, stopwatch and countdown. The grey button on the front at the bottom is the illumination button. Pressed once the screen is illuminated for a few seconds - hold it for longer illumination.
The tidal display is at the top. In the illustration, there are two "bars" at the right - it is after High Water. In an hour or two the bars will have "moved to the right to the left hand side of the screen", will be smaller, then will move further to the right and be smaller still; Low Water - above the number "zero" part of 10 in the illustration. They will then continue to move progressively right and become larger until the top of the "curve" above the number 8 in the illustration.
Others have criticised the strap, saying it is flimsy. It is perfectly adequate - if my watch catches on an anchor chain, I'd rather the strap broke than my wrist! I wouldn't dream of wearing my Timex which has a leather strap for anchor work...