Overview: Features a flashable EEPROMBy upgrading the built-in unlock chip, this attachment can stay up-to-date with maximized compatibility with the latest cell phones To upgrade, you need a USB (Universal Serial Bus) SIM card reader/writer (sold separately). Simply slide the attachment together with a (any) SIM card into your SIM card reader, then download & launch the utility downloaded from the above link. Specification: Dimensions: 0 in x 0 in x 0 in Weight: 0.05 oz