The main appeal of the iM500 is its ultra-thin profile. The iPod dock section and rear stand fold into the speaker, and when it is closed, the whole thing is only 17mm thick -- about the same as a DVD case. Pressing a button in the centre of the speaker makes the parts pop out with a satisfying click.

There are only three buttons on the iM500: a power key to the left of the nano dock, and volume up/down buttons on the right. They are small, not very tactile, and you need to press down hard for them to perform their functions.

The back of the unit features a USB connection, two battery compartments that each hold three AAA cells, and sockets for the AC adaptor and aux input.

The iM500 is quite light at 340g, but although this makes it easy to tote around, the low weight has some negative effects. Because the nano sits flush against the speaker, there is no way to hold onto it while you are using the clickwheel. This means that you must use both hands when navigating menu options -- one to press the buttons on the player, and one to hold the speaker steady, otherwise it will move around. Unlike other docks we've seen on iPod speakers, the iM500's nano connection consists of only a plug, with nothing surrounding the nano to keep it steady. The omission of a more substantial holder may have been essential in order to preserve the folding design, but it results in the nano wobbling back and forth when the speaker is moved even slightly.

Features
The iM500 allows an iPod nano to be charged via the included AC adaptor, as is standard for most iPod speaker attachments. Less common, and quite nifty, is the ability to sync the nano with the iTunes library on your computer using a USB connection.

The speaker can be operated by either mains power or six AAA batteries. The AC adaptor is 100-240V, and international plug adaptors are included -- a nice touch that will please frequent travellers. A carry case rounds out the accessories.

Performance
We're sorry to say it, but as much as we wanted to like it, the iM500 had some significant performance issues. At moderate to high volumes, a background hiss crept into the sound, and both bass and treble became muffled. Choosing the "Treble Booster" equaliser setting on the nano improved matters a little, but there was still the ambient fuzz to contend with. In the troubleshooting section of the user manual, the advice given for the problem of distorted or crackling sound is that the volume must be set too high. But what if we want to have a bit of a stress relieving Acca Dacca rock-out air guitar? It seems it must be done at low volume for the music to sound any good.

As with Altec Lansing's inMotion iM9, the volume defaults to a "Whoops, sorry neighbours" level when the power is turned off then on again. It should also be noted that changing the volume on the iPod nano has no effect on the sound level.

While the slim profile and folding design are very cool, too many sacrifices have been made in terms of usability. The iM500 might appeal if you want an easily portable way to listen to your nano without headphones (at low volumes), but overall we were disappointed.