With 4GB of flash memory, this Sony Digital Voice Recorder has the capacity to hold over 1,000 hours of recorded speech. You can use it to record your own voice for reminders or personal dictation, lectures at school or discussions at business meetings for later reference. A memory card (sold separately) can be inserted into the Sony Voice Recorder's expansion slot to create additional storage space. You can separate each recorded file into up to 98 tracks so you can easily navigate to the part you need to listen to.