Samsung's new Z400 looks remarkably similar to the D600, but it adds 3G capabilities to what was an already delightful handset. The Z400 also comes in a stylish silver colour scheme and features a unique mobile tracking system for extra security.

The tri-band and 3G Z400 is a stylish and sleek handset thanks to its compact dimensions, rounded edges and light weight. Only a touch larger than the D600, the Z400 measures 96.7mm x 47.8mm x 19.2mm and weighs just 107 grams. It is comfortable to hold in your hand and the excellent sliding mechanism is easy to open and close thanks to a well implemented spring system. The Z400 doesn't require much force to slide open and can be operated comfortably with just one hand.

The design is very similar to Samsung's previous handsets, with only minor changes. Remaining are the simple and easy to use controls - a five-way navigational pad, two selection buttons, answer and end call keys as well as a clear button. A volume key and microSD card slot are also present on the left and dedicated camera button and shortcut key on the right. The handset has slightly more rounded edges than previous models.

Slid open, the Z400 reveals a compact, but well placed and comfortable keypad. Its keys are perhaps a little flat, although they don't require a firm press to activate so we were able to punch out fairly fast SMS messages. If you have large fingers though, you'll find the small space between the 1, 2 and 3 keys and the bottom of the slider cramped.

The Z400 has an excellent bright, clear and overly crisp display. With a resolution of 240 x 320 pixels and capable of displaying 262,144 colours, the QVGA screen is one of the best we've seen on a mobile phone. On the down side, we did find the display picked up its fair share of fingerprints smudges and was near impossible to keep clean.

Phone Thieves Tracked!

The most interesting and unique feature of the Z400 is its mobile tracker system. This is a new security feature that we haven't seen on a mobile phone to date. When a SIM card in the Z400 is replaced, the mobile tracker sends an SMS message to an earlier nominated phone number, revealing the mobile phone number of the new SIM card. This is a very useful feature and although it doesn't prevent theft, it may make many people think twice before attempting to steal your phone.

Unfortunately the Z400 lacks push email, although it does support standard email access via POP3 and IMAP4. The phone still supports SMS, MMS and standard email messaging with T9 predictive text input though, and there's Bluetooth and USB for connectivity and WAP 2.0 for web browsing. Samsung also offers a media player with limited playback controls such as shuffle and repeat. The media player features visualisations, 3D sound options and equalisation settings, but its biggest flaw is the fact that users are still unable to use any other phone functions, such as messaging, while listening to music.

The Z400 also features a voice recorder and a document viewer. The latter allows users to upload documents such as Word and Excel files to your phone for viewing. One feature not included is the TV-output option. The D600 featured a cable which allowed users to connect the phone to any television with a composite AV input. In theory it was an excellent idea but we found most documents, such as Microsoft Word files, to be unreadable due to the low 320 x 240 output resolution.

The Z400 includes a 2 megapixel fixed focus camera. We found the image quality for most part was fairly good for a camera phone and the range of shooting options included was impressive. A multi-shot mode is available, where six, nine or fifteen images can be taken at the speed of two photos per second. We particularly liked the mosaic mode also - you choose from 15 different templates that include multiple layers and each photo taken is stamped onto one layer. Other features of the Z400 include a calculator, world clock, converter, memo and alarm functions.

Unfortunately, the Z400 is let down by a poor battery life, with Samsung quoting figures of 2.45 hours of talk time and up to 250 hours of standby time on the 3G network. These slightly improve on the 2G network, with 3.1 hours of talk time and up to 330 hours of standby time. We found we had to charge the phone every two nights with only moderate usage.

Overall the Z400 is another great release from Samsung. It is an attractive and feature packed 3G capable handset housed in a sleek and stylish slider design. Battery life is the only disappointment.