Like a regular SIM, the micro-SIM holds your subscriber information for the carrier and is great for storing phone book contacts and other personal information. Micro-SIMs are user-replaceable and slide into a little slot in your device just like regular SIMs.

The micro-SIM is a smaller version of a SIM card found in your mobile phone, but holds exactly the same functions and micro-applications. The size of the micro-SIM is about a half of a regular SIM card (12x15 mm instead of 15x25mm).Though it contains the same information, it is not physically compatible with regular SIM cards found in your mobile phone.

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Is a micro-SIM the same thing as a micro-SD card?