'MP3' is now claimed to be more often searched for than 'sex' on the Internet and the current fad for digital music shows no signs of reaching a peak. One of the main players (literally) in the MP3 boom is Diamond Multimedia's Rio device and the latest version, the Rio 500, is better than its predecessors in most respects. Slightly smaller than a typical packet of cigarettes, the Rio 500 is light and easily carried in the supplied pouch, clipped to your belt. It needs only one AA battery, which lasts for up to 13 hours of playback, so is very light and convenient. The device is available in silver or translucent teal or purple.

The Rio 500 has a back-lit LCD display which shows the track name, artist and other information. You can adjust the volume and use the built-in equaliser to set the device for different music types. Four buttons on the front face work like tape transport buttons for starting, stopping and track selection. A socket at the side takes the supplied lead to connect to any USB port on your PC or Mac - there's no traditional serial connection.

64MB of flash memory is built in, which is enough for around 16, four minute music tracks or up to three hours of pre-recorded speech. There are growing libraries of talking books available from Net sites like audible.com and Diamond's own rioport.com, much of which free. Add that to the ten of thousands of music tracks available from MP3 sites and there's no shortage of material to listen to.

The effectiveness of any MP3 player depends on the ease with which you can download sounds. In Diamond's case this is pretty straightforward, and the supplied Audio Manager is all-embracing. The same application handles recording of CD tracks, browsing the Internet for MP3 files, compiling a database on your hard drive and downloading to your Rio 500. It does all this in a fairly self-explanatory way... which is just as well.

Where the software is well designed, the accompanying documentation is poor. A couple of pages of text is all you get, mainly devoted to the PC and Mac software. There's little about the workings of the player itself and some aspects, like the need for folders in the Rio's file structure, are given no explanation at all. It would only take a little extra effort to provide all the necessary details, so why couldn't Diamond manage it?

This niggle aside, the Rio 500 works extremely well, but as with all MP3 players, you have to be quite dedicated to reload it each night with new sounds for the following day. What we need is a Rio with a gigabyte or more of internal storage. That may not be long in coming.

Diamond - Rio 500 features - Verdict

With double the internal memory of the Rio 300, and room for an extra 32MB in a SmartMedia card, the Rio 500 is easy to use and very convenient. Music playback is clear, if a little bass-light, and overall Diamond's device shows the way for music on the move.

Diamond - Rio 500 price

£210 inc. VAT

Diamond: 01189 444400