Samsung Galaxy S III/S3 GT-I9300 Factory Unlocked Phone - International Version: I own a Galaxy S2 and switching my old SIM Card was a breeze. I bought the S III for my wife and opened up the back to transfer her SIM and realized that I needed a MicroSIM Card. Did the normal on-line checks and found that a work-around was possible by cutting the old SIM Card. However, here is what you need to know: My Mobile Provider advised that my existing (normal) SIM Card (2009 vintage - 25mm x 16mm) was not sized to cut to the MicroSIM size (15mm x 11mm) as the chip was too close to the latter dimension. For $3.49 they sold me the new style normal SIM Card (25mm x 16 mm) with the chip being much smaller than before (12mm x 9mm). The new SIM Card was 'activated' with my existing number and then cut with a cutter (like the Clearmax Micro SIM Cutter from Amazon). With an adaptor, I transferred all my contacts to the MicroSIM Card and installed in the new S3 Phone. Phone in service. She loves it! Maybe 4 Stars as neither BLUTEKUSA, AMAZON nor SAMSUNG advised customers. Recommend that AMAZON puts this advisory in their Product Description.