When deciding on a mobile phone, it is important to consider the right form factor not only for aesthetic purposes, but for ease of use as well. All of the phones on the market can be broken down into several rough categories: clamshell, slide, swivel, and candy bar. There are variations on these categories, including the dual slide action and others.

Clamshell

The clamshell is one of the most recognizable of all the mobile phone form factors available on the market today, and consists of two sections that fold onto each other at a central common hinge. One example of this form factor is the Motorola RAZR, a phone marketed for its very slim design. This phone is offered on the GSM and CDMA networks, and is filled with all of the latest features, including microSD support, Bluetooth, MP3 ringtones, music playback, MP4 video playback, and a VGA camera.

The slide phone is one that has two separate segments that slide past each other, in order to conceal a keypad or mini keyboard. A dual slide action is one that slides in one direction to reveal an input surface, and another direction to reveal a separate input surface. An example of a slide phone is the Helio Ocean, that has one slide that exposes a number pad, and the other displays a full keyboard. The Helio Ocean has advanced capabilities, including GPS navigation, the Opera Mini browser, multimedia player with video and audio support, document viewing, image viewing, instant messaging support, email, YouTube, and so much more.

The swivel phone is one unique interpretation of mobile device design in which one segment swivels under another. This is present in the Samsung U470 Juke phone, which has a very narrow profile with keys that swivel under the screen to provide the form of a small mp3 player. The Juke has a built-in 2GB storage space for music, as the key feature is the music playback capability. The Juke will play the WMA, WMA Pro, AAC, AAC+, and MP3 formats, and has a built in VGA camera with a night shot mode.

The final form factor is known as the bar, candy bar, or slab design. These devices are in a flat cuboid shape, with the buttons, keypad, and screen exposed. Two companies known for phones of this form are Sony Ericsson and Nokia. A very famous example of a bar phone is the Apple iPhone. The iPhone is a slab phone with no keypad, but instead a multi-touch screen that will accept and accurately interpret the input from more than one finger at once. The Apple iPhone runs on a stripped down, but complete version of Apple's OS X operating system. This allows the phone to have one, if not the best platform for mobile application development, as well as the full Safari web browser. This phone also supports full email with a document viewer for attachments, a Wi-Fi iTunes store, YouTube support, 3G networking, maps with A-GPS, and much, much more.