I've bought two now. They're junk. Neither one lasted more than a month before it started to fail.
I love the concept and the aesthetic design. The quality, however, it horrid. It's a device designed to float in a pool full of water, outdoors, in the weather and, yet, it's incapable of keeping the water out. It leaks like a sieve.
Best as I can tell, the water is penetrating around the LCD display as there is no water seal between the display and the clear window (see attached photos), but I can't confirm that. Either way, it'll work great for a few weeks, then you'll start to notice a little condensation on the LCD glass. Then it'll start to report water temperatures over 100, under 50 (in Florida in July), and stop working.
It's a shame, really. But, it's a complete and utter waste of your money unless you're handy with tools and willing to tear a unit apart to waterproof it before you put it in the pool. A horrible design job.
The unit I used for the attached photos is less than two months old, bought brand new and the local Home Depot. I think I'll see if they'll exchange it and then take that apart and waterproof it and see how that goes.