IMAGE&reg; USB Vibration Speaker with Micro SD Card Slot (Can Act as Stand Alone MP3 Player) Audio output: 3.5mm audio cable. Input DC voltage: DC 5V. Frequency: 80Hz-18KHz. Impendance: 2ohm. Distortion Factor: =&lt;0.5%. Rechargeable with built in Lithium battery which allows it to used away from your computer and on the go. TransFlash Slot (Micro SD card is not included). Handles up to 16GB Micro SD card. This allows you to play your MP3 files without being connected to any power or music source and play 360 degree sound. This is not the entry level model without the battery or TF Slot, this is the newest model available that can act as a stand alone MP3 player. Power Supply: This product can be powered through a USB port or will operate using the built in lithium battery. Sound Source: It can be connected to any 3.5mm stereo jack or it can operate using the built in TF card (Micro SD) card slot. Package included: 1 x Vibration Speaker(TF card is not included), 1 x Mini USB to USB Cable with 3.5mm Audio Cable, 1 x User Manual.