Losing your mobile phone could be a nightmare! The most distressing part of this experience is the loss of your phone numbers and contacts stored on your sim card. Never fear, with this unit  you are able to store a backup copy of your SIM card data and transfer the info back into a new sim card when needed. Transferring data between phones could hardly be simpler than using this clever little device. Just slip in  your SIM card, press the 'Backup' button and 'hey presto' - the card's data is transferred to the reader.  Restoring SIM data is just as simple with just one button to press to write data back to the card.  Size 45 (W) x 65 (H) x 15 (D )mm.  Uses 1 x CR2025 battery. Use our SB-2520 when replacement required.