AS THE MATCHING PROBLEM,IF NOT WORK,WE CAN REFUND DIRECTLY?-- Only support the U-DISK,can't charge for your phone or other device!. ONLY SUPPORT MP3 MUSIC FORMAT?-- This aux cable only support MP3 Music Format,and don't make file in your U-DISK and don't store other documents. ONLY SUPPORT SMALL U-DISK CAPACITY AND U-DISK ONLY STORE MP3 FILES?-- U disk capacity as far as possible not too large.It depend on the car's AUX audio interface can support how much capacity. CAR NEED MP3 DECODE FUNCTION?-- Please make sure your Aux port has mp3 decode function that can read the mp3 file from U-disk.If your car don't have this function,it will can't work,PLS CONFIRM IT BEFORE YOU BUY!!!. Only Work with Your Car Aux Port?-- This product allows you to play music on your car audio system using your U-Disk/USB Flash Drive with MP3 decoder.