SanDisk SDMSM2-004G-A11M 4GB M2 Memory Stick Micro (Black) Dual voltage operation; 1.8v for new Sony Ericsson mobile phones, 3.3v for Memory Stick PRO Duo compatible devices Controlled ejection design allows for easier removal Sony MagicGate encryption technology support Read/write: 10MB/sec read, 3MB/sec write