You may think of Sony Ericsson's mobiles as either Walkman phones or photography-emphasising Cybershot phones, and it would be fair to do so. But there are other strings to its bow, and the quad-band S500i is an attempt to corner the fashion-conscious market.

This is a slider phone and it comes in two colour schemes. Our review sample was Mysterious Green and you can also get it in Spring Yellow. You don't see much green until you open the slide, though: on the outer casing there is just a lime green backlight for the centre of the navigation button.

Inside, the number-pad surround and the keys themselves are a similar lime colour. The remainder of the casing is mostly black, with silver-grey edges and some silver buttons and button icons. But there are two features that Sony Ericsson thinks make this phone stand out: its sidelights and autochanging themes.

The sidelights amount to pulsating lights in lots of different colours. You can choose from a range including single colours and multiple colour schemes. When an incoming call arrives, the sidelights obligingly pulse in your selected colour scheme.

We'd have liked to be able to select different colours for different callers, differentiating between important and less important people, but you can only make one selection.

There are three themes. One of these changes as the time goes from day to night, another offers you a different theme depending on the time of year. This isn't groundbreaking, but it is a nice touch. Certainly the screen does the themes and other aspects of this phone justice as its 262,000 colours and 320 x 240 pixels are clear and sharp.

In the hand this is a fairly large phone for a slider, being 47mm wide and 14mm thick. It is 99mm tall when closed and grows to around 130mm when opened. It scrapes under the 100g mark by six grams. The slider mechanism is not as springy as it could be, and while the number-pad is large enough for efficient use, a ridge along the bottom of the handset makes getting to the bottom row a bit challenging sometimes.

Worse, though, is the front-mounted navigation key. It's large enough, but its surrounding frame on the fascia is raised so that the narrow silver band you use for movement is not that easy to press at times.

There are plenty of features, ranging from Web browsing and RSS to mobile e-mail, music playback and a 2-megapixel flashless camera (which is average in performance). You only get 12MB of built-in memory, though. You'll need to buy a Memory Stick Micro to add to this as none is provided with the phone.

The features list looks impressive, but the camera is no better than average, the phone is short on memory, and there are some design issues that affect easy use.