Nokia and LG Electronics have both launched new phones that can handle two SIM cards. Offering dual-SIM products has become increasingly important in the last couple of years. They allow users to get better tariffs or switch between SIMs for personal or work use."Particularly in a lot of emerging markets -- India, for example -- dual-SIM support has become an absolute requirement now," said Geoff Blaber, who leads mobile device research at CCS Insight.