We appreciate your interest in the XB23. It comes only with a USB Cable and warranty card. We apologize, this unit doesn't feature an AUDIO IN jack. It is a Bluetooth only model.
If you want to play music, you can use your smartphone and connect it via Bluetooth connection.
You might want to consider getting the XB43, XB12, XB22, XB32, or the XB41 which do have 3.5mm in, but connecting an audio cable to this jack turns off sound output from the connected BLUETOOTH device. I hope this helps!