Dual SIM phones allow users to insert two different SIM cards and manage them at once. Most of these phones employ active Dual SIM tech, meaning that the SIMs work in parallel and you can receive calls and SMS on them at the same time, hassle-free. It is also possible to designate them for different functions; for example, one SIM can handle incoming and outgoing calls, while the other handles data services.
It is an ideal solution for those who want to combine personal and work numbers in one device, or frequent travellers who want to avoid outrageous roaming fees.