Due to the large amount of memory space required for imagery and audio data, the 16 GB Vision 1000 SD card only retains the last four hours or 10 power cycles’ worth of audio and imagery data. The 32 GB SD card can store approximately 8 hours or 10 power cycles’ worth of image and audio data. Inertial (location) data, however, requires significantly less memory space, so the Vision 1000 retains up to 200 hours of inertial data.