The CD & MP3-CD membership plans allow members to rent both the regular CD format, and the MP3-CD format. The selection of regular CD audio books is about 4 times the selection of MP3-CD audio books. MP3-CDs are CDs that contain MP3 audio files. 15 hours of MP3 audio files can fit on a single CD, where only 70 minutes of regular audio files can fit on a single CD. The CD & MP3-CD membership plans are for those who do not have an MP3-CD compatible play, or for those who like the convenience of the MP3-CD audio books, but like the greater selection of the regular CD audio books.
The MP3-CD plans allow members to rent MP3-CDs only. MP3-CDs are half the price of regular CD audio books which is why the MP3-CD only membership plans are less expensive than the regular CD plans. You must have an MP3-CD compatible player to play MP3-CDs. Most new players support MP3-CDs, in addition, MP3-CDs can be played in computers and most DVD players. The MP3 audio files on the MP3-CDs can also be copied to a portable MP3 player such as the iPod. The selection of audio books on MP3-CDs is not as great as regular CD audio books but are more convenient and less expensive.