I do not recommend either the seller or the products sold.
It was necessary to remotely control the electric heating via WIFI. For which the GSM WIFI Boiler module was purchased.OK 3.0. After installing the device and turning on the heat support function, it began to periodically issue an error - a malfunction of the wired sensor. After the error, the module went into emergency mode and no longer performed its task of maintaining the set temperature. The problem was treated only by rebooting the device, for which it was necessary to disconnect its power from the mains and from the battery.
After contacting the seller, attempts were made to fix the error:
1. Unscrew-fasten the contacts, flashing the module. I managed it on my own, but it didn't help.
2. Next, the module was sent for a weekly diagnosis to the seller - alas, it did not help. The next step - replacing the wired sensor - is also unsuccessful. And finally, replacing the module itself - unfortunately, it didn't help either.
All this fuss took about two months. The module had to be transported to Minsk to hell in the middle of nowhere, and the distance from the place of its installation to the seller was about 90 km. The seller threw up his hands, assured that this was the first time he had encountered such a thing and praised the almost flawless operation of such modules. But it turned out that I'm not the only one with such a problem. We managed to find a person who purchased exactly the same module from the same seller, who gave exactly the same error. It turned out that it was a matter of bad contacts and the seller knew about it. The contacts are on screws, but the person just soldered them to the module and lo and behold, the device has been working flawlessly for two months.
The story ended with a refund. If you don't want to waste your nerves and time, choose another seller and manufacturer.