The transmitter comes with a USB (charging) cable, an adapter RCA to 3.5 mm jack and a German manual. The latter is written in a rather droll industry typically German, but understandable and perfectly adequate in scope. In the manual is, moreover, explained that the device can be used during charging and that the internal memory can hold only 8 coupling partner, so you have to empty it when you want to pair with a device 9 (and it is also described , how to do that).
The pairs with the headphones funktuioniert with me quickly and easily. The reception is very good, the coverage rather larger than the mentioned 10 m (doors, walls or windows do not disturb) - only when I go to another floor, breaking the receipt from (through the reinforced concrete ceiling but also penetrates the wireless router barely by). I have the entire garden without any problems receiving, except when I close (metal!) Blinds. Battery life is fine (a few hours - properly tested I have not yet).
The sound quality is both in connection of the jack to a headphone output as well as when using the RCA adapter very well, but you must be careful when connecting to a (pre-amplified) headphone output that the level of the amplifier is not regulated too high, otherwise the overdriven Transmitter quickly, which then no longer sounds so delicious. So the device select the volume in doubt rather low and for crank up more on headphones ...
The described delay of the signal actually exists (with me about 0.2-0.5 s). I find that even when watching TV but only annoying when I leave at the same time through the speakers - but why should I put on the headphones, then? How that looks at the dragons, I can not judge ...
Yet something fundamental: This thing is a transmitter which transmits an audio signal from a jack or RCA connection via Bluetooth. Why should you want to connect as part of a mobile phone, reveals itself not me (I would imagine that this other Bluetooth protocols would be needed). So: The transmitter is plugged into a headphone jack on tablet, phone, stereo or TV and paired with a Bluetooth-enabled playback device (headphones, headset, active speakers, etc.). Then it'll work well with the neighbors ;-)
Overall, I am so far fully satisfied, the part does what it should, and is small, light and simple. The price / performance ratio is excellent in my opinion.
A star deduction I give anyway, because you can set the PIN for the coupling does not specify what will inevitably eventually give while pairing with any well fix programmed Kopfhöhrern a problem (the problem but most of these small components - after all, is here in the manual pointed and listed on which pins the device knows) and because the cord is very thin and fragile. I can not say anything about the long-term stability of the part - if necessary I will come back and pull off a few stars ...