Pocket-size design is ultra compact and lightweight for superior portability. Convenient keyhole design for easy attachment to keychains or bags. Square shape with a polished frame and textured surface. Shock-resistant design can withstand minor drops and bumps. Performance read and write speeds up to 540MB/s and 500MB/s (Performance results may vary, depending on system platform, software, interface, and capacity). The PC60 contains massive storage space. 3D NAND Flash technology allows it to store a deceptively large amount of data, up to 4TB. At averages of 4MB per song or 6MB per photo, that's enough space for up to 480,000 songs or 320,000 photos.