A:Answer Hello Doug, thank you for your message. 4 GB of available internal flash memory provides ample space for recording life’s important moments-up to 1,073 hours in fact. You can use microSD/microSDHC memory cards with the IC recorder. (However, microSDXC cards are not supported.) Due to the file system specifications of the IC recorder, you can record and play back an LPCM file smaller than 2 GB (ICD-UX533/UX533F/UX534F only), and an MP3/WMA/AAC-LC file smaller than 1 GB using a microSD card. For more information, check the link below: https://docs.sony.com/release/SPECS/ICDUX533_mksp.pdf. - Oscar.