The review is made having the product for just one day in my possession; if anything changes, I will come back with an edit.

+ Listening to music from Spotify, YouTube, etc., through the phone, in a car that does not have Bluetooth or Android Auto.
- However, it often has interference (tested in Athens, where it is extremely difficult to find a clear frequency), the sound quality is mediocre with a tendency towards good if you are in an area that favors minimal interference. Those of you who think you will listen to your favorite music in quality, just forget it.
+ Mobile calls through the car speakers and a built-in microphone in the transmitter. I could hear my conversation partner very well, and he could hear me the same, I was stopped with the windows closed.
+ Mobile charger with the classic USB port and also type C. It is supposed to support fast charge, but I haven't tested it yet.
+ You have all the above together in a small device.

At 29.90, I would describe it as an honest little gadget that gives you the ability to do some things you could only do by purchasing an OEM that costs 200+ euros.
Okay, you will make some concessions, but you should also know what to expect from a product.

********* EDIT ******** 21/09/2024
Having had the product for a few months, I have to say the following:
---For music, I now use it rarely to not at all. I have found 2 clear frequencies for Attica with almost zero interference, but the sound quality does not satisfy me; this is an issue that all transmitters face, not just this one.
---For open listening on calls, it does its job quite well, better than I expected as I was very cautious about how my conversation partner would hear me due to its position, which is low behind the gear lever. They can hear me well even with the car in motion as long as the windows are closed.
---Its charging is quite satisfactory given the proportions. I consider this a positive.
---I do not regret purchasing it nor am I disappointed BECAUSE from the beginning I knew what to expect. As for the music, it is a solution of necessity, let's say (for my tastes, as I am a fan of quality listening) ... for calls and charging, it does its job well to very well.