These models are at the opposite end of the flash players and play actual CD's that have MP3 formatted music on them. Most current CD players can recognize MP3 music and the size of these players can not get smaller than the CD in them.
Say MP3 player and most people will not take this player into consideration. In fact, if the size of the player is not that important and you are just going to use the player in the car, stick with the CD player. Most people do not want to spend a large amount of time transferring music files to their MP3 player. Getting the digital music files you want downloaded to your computer and then onto your player requires attention and energy.
If you have the music you wish to listen to on CDs already, invest in a very good portable CD player and headphones. But if downloading music is not a huge effort and the need for a small player is, MP3 players are the way to go.