If you - like me - small speakers would have on the go, which can be used with an iPod / iPhone, MP3 player, etc., you should stay away from the boxes. Because the boxes will only work if they are (with the supplied USB port) connects to a power source and have, unfortunately, no battery to charge it can.
The sound quality is impeccable and you also get a proper volume for the small boxes out. Therefore, there are still 2 stars from my side - even if the boxes have not complied with my wishes. I will then search times ...