Amazon.com: Rechargeable AM / FM/SW Radio Small shortwave Radio/Wide FM Compatible / MP3 Player, Convenient to Carry, with Bluetooth Function, USB Memory/TF Card Compatible Radio/Speaker (Gold)… : Electronics
3 Shortcuts to Increase MP3 Volume – Easily and Quickly
3 Shortcuts to Increase MP3 Volume – Easily and Quickly
How to play all your MP3's at the same volume - YouTube