The Dashcam 45 can hold up to a 64GB micro SD with a speed rating of class 10 or higher. The recording time depends on whether you have the camera fully charged or plugged into a power supply or hard wired. The recording time also depends on your SD card size. A smaller card will hold less data and will have data over written. You can find more answers at http://static.garmin.com/pumac/DashCam_45-55_OM_EN.pdf