After the YouTube video is converted to an .mp3 file, you need an mp3 player to listen to it.
There are many brands and sizes of mp3 players. The most famous of these are Apple iPods.
Mp3 players are also produced by Samsung, Acer and Philips. There are also ones integrated in smartphones and mobile phones.
The software provided allows one to download mp3 files using the cable normally provided with the player.
Portable mp3 players have an internal flash memory which can range in size from a few gigabytes to 64 or even 128 GB.
Mp3 files, however, can be played not only on portable devices but also with software installed on a computer.
The most famous software programs are winamp, Windows Media Player and VLC Media Player.