Sondpex CSF-D45B Portable Bluetooth Speaker System and Music Player Crisp, clear sound and heavy bass;Connect to any computer, smart phone, or device with a 3.5mm headphone jack through AUX input Built-in Bluetooth USB and SD card Slots (supports up to 32GB of memory each) Supports MP3/WMA music files Built-in lithium battery lasts up to 12 hours