... Unfortunately failed us the SD card slot. Why only 4 stars. To connect an MP3 player or USB stick worked well. While reading the data takes quite long but it funkionierte unlike the used SD card. This was recorded with different MP3s and stored in different folders. Unfortunately, the reader could out there get no sound. Perhaps a single error. Optics and service very good. The sound is for the price and our purpose pursued (in the bathroom) perfectly adequate, perhaps a little too bass heavy, but who obtains a fully functioning unit, is sure to peace with it.