Micro SD PRO voice Recorders come with built in memory and an expandable micro sd slot. microSD is a format for removable flash memory cards. SD  is an acronym for Secure Digital. The cards are commonly used in mobile phones, as well as in some newer handheld GPS  devices, portable media players, digital audio players, expandable USB flash memory drives, Nintendo DS flashcarts, and digital cameras. microSD cards are available in capacities from 64 MB to 32 GB. To purchase Micro SD cards and memory cards please visit our suggested Micro SD Cards on Amazon