Great functional watch. The F91W is noticeably thinner and lighter than the F105W so is less likely to get in your way. The greenish-yellow light from the side - while dimmer than the backlit F105W - is also bright enough for its purpose. Watch face looks a bit nicer than the F105W in my view.
For those who need to know: a 4 second press of the right hand button shows up "C A S I o", and holding all three buttons displays all available LCD segments at once. Precision is good.
This is the classic Casio digital watch from my childhood. A really really classic digital watch. It’s simple, clean with three buttons, an easy-to-read face, alarm chronograph and a back light. It’s cheap, robust, and straightforward. And mostly memorable...