Thermomètre à eau submersible

The thermometer doesn’t work. It is stuck on 10 degrees. The outside box was sealed. But the inside packaging had been opened. I’m wondering if this is a return that was resent out.

This thermometer is the best one so far. There’s been three. This has blue display which makes it very easy to read. It is also the most accurate thermometer I’ve purchased. It’s placed directly in the water and I pull it up by the string when I want to check the water temperature. I use it in a 10 gallon aquarium, not a pond. FYI This item came with a cryptic cancer warning. I’ve provided an image of it. Despite that, I recommend this item, I’m pleased with it. I hope this helps. Thank you.

It's working so far would be nicer if the color inside the thermometer was red so it was easier to read against the black background having blackish blue mercury doesn't make it easy