The vast majority of portable digital audio players use either Flash memory or a hard drive to store the MP3 or WMA files that you transfer from your PC. There are also a few players that use removable media such as SD, but then we come to a fourth - more obscure - type of player.

Generally when you burn an audio CD from MP3 using your CD writer, your PC decodes the MP3 files and converts them back to regular CD format so you can play the CD in your car, on your hi-fi or in a portable CD player. A CD MP3 player (they don't seem to have a specific name) can read a CD that has MP3 or WMA files on it and can then decode them as it plays the music.

That means you can get about ten albums onto a single CD, and you can also take out one CD and replace it with another as the media isn't fixed. Of course that means that the player has to be large enough to accommodate a CD, but the Panasonic SL-CT810 is almost exactly the same size as a CD jewel case.

As CD players go it is quite expensive because it supports HighMat (High-performance Media Access Technology) which is a technology that was developed by Panasonic and Microsoft to help you manage your media files using metadata tags.

The Microsoft involvement means that HighMat favours Windows Media Player 9 and Windows XP over other software, but that is no surprise. The in-line remote control includes a small display, and if you use HighMat the track data will scroll across it.

This is a stunning CD player but it is necessarily quite big compared to the other players in this group. However, it offers very fair value for money.