Mobile handsets

Also known as the "flip phone" clamshells are neat and trim enough for the smallest handbag or pocket, but flip open and the clam shell extends into a mobile phone. Think Sex & the City, Niles Crane, Motorola RAZR.

• Advantages: slick, neat, the screen and keypad are protected as they are covered
• Disadvantages: has to be opened up to make a standard phone call

Like the clamshell, the candybar is a top choice of mobile and the closest to the traditional mobile format. The candybar has its buttons exposed and available with no hinged or sliding parts.

• Advantages: small, quick access to the screen and buttons, just tap and dial
• Disadvantages: the keypad needs to be locked (unless you want your phone calling your first contact number from inside your pocket), the screen is always exposed

Very broadly speaking, a smart phone is any type of handset loaded with the latest technology and advanced PDA type functions. Primarily marketed to businessmen on the move, the smart phone is muscling in on the BlackBerry market.

• Advantages – hugely capable phone, intuitive and powerful operating systems, reliable PC compatibility
• Disadvantages – generally larger than standard handsets, more expensive, high replacement cost

The slider uses any of several very crafty mechanisms to reveal either the screen or the keypad. First popularised by the cult film the “Matrix”, sliders are experiencing something of a boom these days, as handset manufacturers recognise its hidden features, benefits and nifty feel.

• Advantages – protected keypad or screen, can be larger and easier to use when open and compact when closed
• Disadvantages – has to change shape to be fully used.