Unacceptable. I have nothing to comment,
1. there are no instructions for use.
2. it broke in 1 hour, LUCKILY I TRIED IT IN ANOTHER AQUARIUM WITHOUT ANY LIVE ANIMALS INSIDE.
3. I called the store and they said, uh I don't know what to tell you, it happens. Also, when I asked them about how it works, they told me they know nothing about the product they are selling.

After 2 months I can say that it works, but to get the water to 25 you have to set it to 28

I have put it in a 60-liter aquarium, it works just fine, I just set the temperature to 27 so that it stays at 24! So it works perfectly fine

It works outside the aquarium so it works, I haven't put it to work inside the aquarium yet but I believe it's very good, time will tell...

I was not at all satisfied with the product. I ordered it twice. The first one broke immediately and the second one that arrived does not work. The water is always cold and the thermostat does not turn on at all.

This is my first time using it, so I don't know if everything is like this. For this specific one to keep the aquarium at 23 degrees (according to the thermometer), the switch needs to be turned to 29. So far, it seems good for a 20-liter aquarium; I've had it for 3-4 days, and I will return for an update in a few months.

I left it half out of the water for a little while, the next day it was smoking and broke. Luckily, my turtle wasn't inside

Both purchased from the same store broke. During the breakage of the second one, the water temperature rose so much that the turtles nearly boiled. Fortunately, we were home and caught them in time. Very bad purchase.

It works only in the morning hours and for no more than 2 hours, and for the rest of the day, it is in hibernation, so it does not raise the temperature above 22°C, and this in the morning and this in a 17-liter aquarium. Unfortunately, wasted money.

I found it to be very good quality and packaging. It doesn't seem easy to break. Its temperature matches the reading on the aquarium thermometer. Very economical, so I am very satisfied.

I bought 2 of these thermostats and I use them in water containers of the same volume (~20L), under stirring. I wanted them to keep the water at 24-25C. Even in larger containers (50L), neither of the 2 thermostats heats the water properly. After a lot of effort, I managed to find the ideal settings. One had to be set to 27C to keep it at 24-25, while the other had to be set to 29-30C.

Overheating and the glass cracked and I haven't used it for even a week. Very disappointed