The Sony 4GB Compact Flash 133x memory card is designed specifically to help advanced amateur or professional photographers get the best performance from their high-end imaging devices and applications. No matter how fast you work, Sony cards can keep pace with its ultra-fast transfer rates of 20MB/sec. read and 20MB/sec. write. The cards high capacity means you can capture more continuous, high-resolution images, and when it's time to transfer your largest files, the high speed rating of these cards means that your production workflow will be more efficient than ever.