HiLetgo Mini Logging Recorder Data Logger Module Shield V1.0 For Arduino UNO SD Card SD card interface works with FAT16 or FAT32 formatted cards. 3.3V level shifter circuitry prevents damage to your SD card. Real time clock (RTC) keeps the time going even when the Arduino is unplugged. Included libraries and example code for both SD and RTC, means you can get going quickly. Prototyping area for soldering connectors, circuitry or sensors.