As the many of people already know, in general iPhone's are sold in a locked condition, restricting their use to one particular network carrier. Unlike most GSM phones however, an iPhone cannot be unlocked by simply entering an unlock code. The locked/unlocked state of an iPhone is identified by it's unique IMEI number and is maintained on Apple’s server. This locked/unlocked status is set when the handset is activated in iTunes.
This official method of unlocking an iPhone (when an iPhone status is set as UNLOCKED on Apple's server) is also known as an iPhone factory unlock or iPhone IMEI unlock and is usually only provided directly by the network the iPhone is locked to. BUT carriers will refuse to unlock an iPhone unless strict unlocking criteria is met.
The unlocks we provide are permanent, work with any iPhone model, operating system (iOS) and baseband version, and once unlocked, enable an iPhone to be used with any GSM network carrier, anywhere in the world.
For a full list of features, supported handset and networks, please see below: