Very beautiful and not bulky head. I found them at a good price and because I also have the Smarther thermostat, they connect directly on it and create a temperature control network in all rooms. The thermostatic switches need to be installed and tested. I will come back with an update

Incredible product. First of all, I have to say that I have a Legrand Smarther 049039 thermostat to which the heads are connected (they can also be connected to other smarter thermostats from Legrand as well as to Netatmo, but check compatibility before doing anything), otherwise you need to get the kit.
-The heads have a thermostat and take batteries (batteries are included in the packaging).
-The heads automatically turn the radiator valve, but you need to install automatic valves for the head to turn them (my plumber who maintains my boiler saw the heads and found what I needed to get). If you already have automatic valves, they may be compatible with what is inside the box.
-The connection to the network is very simple, for me it was through the Legrand application. Once you insert the batteries, the application detects them. If too much time passes and you haven't connected them, they stop appearing for connection, simply remove the batteries and put them back in, and they will appear again (ideally, attach the battery covers when you are about to make the connection to avoid losing them).
-Through the Legrand application, you can adjust the temperature you want in the room where the head is located.
-You can also change the temperatures in the heads using voice commands from a smart home system (I have Google Home).
-After connecting to the application, you need to calibrate them through the application so that they can open and close the radiator valve correctly. Once this is done, the exclamation mark that appears disappears and everything is ready.
-The head can even turn on the boiler for just one radiator, and when the room reaches the desired temperature, it turns off the boiler.
-If you have a Legrand Smarther, you can program the heads for the entire 24-hour period, just like with the thermostat, so the room temperature is automatically adjusted all day. For example, for the thermostat, I set it to 22.5 when I'm at home, it goes down to 20 when I go to work, one hour before I finish work it goes up to 22.5, and at night after 01:00 it goes down to 19.5 until one hour before I wake up, and it automatically goes up to 23. This can be done for each head, so you can understand the benefits.

This year is the first year I have used them, and I expect to see savings as soon as I installed the Legrand Smarther thermostat 049039 two years ago, I noticed a big difference. The heads work perfectly, they have never disconnected, and they always turn when I change the desired room temperature.
I consider them quite expensive. I bought them for €60 on Black Friday last year, and now I regret not buying them for three more radiators. I only installed them in the bedrooms, and I think they are enough because it is a crucial space where you want the right temperatures.