Samsung is setting out to impress at this week's 3GSM trade show in Barcelona by unveiling what it said is the slimmest cellphone handset in the world. The phone is one of four new handsets that refresh the company's Ultra line of phones that was first unveiled about eight months ago.

The Ultra 5.9 is, as its name suggests, just 5.9 millimetres thick. That's a millimetre thinner than the candybar form-factor phone it replaces in the Ultra range. It looks similar to the previous model, has a 3-megapixel camera and is compatible with the GSM standard.

Also introduced Monday was the clamshell Ultra 9.6 and two sliders, the Ultra 10.9 and 12.6. All three have 3-megapixel class digital cameras. The Ultra 9.6 is a tri-band GSM model, the Ultra 10.9 is a quad-band GSM model and the Ultra 12.9 is tri-band GSM with WCDMA (Wideband Code Division Multiple Access) 3G and HSDPA (high-speed downlink packet access) data.

The four phones are due on sale in the European market during the current quarter. Launch details for other markets were not disclosed.