The module (MicroSD Card Adapter) is a Micro SD card reader module, through the file system and the SPI interface driver, SCM system to complete the file to read and write MicroSD card. Arduino users can directly use the Arduino IDE comes with an SD card to complete the library card initialization and read
The RC522 is a 13.56MHz RFID module that is based on the MFRC522 controller from NXP semiconductors. The module can supports I2C, SPI and UART and normally is shipped with a RFID card and key fob. It is commonly used in attendance systems and other person/object identification applications.
The Arduino Nano is a small, complete, and breadboard-friendly board based on the ATmega328 (Arduino Nano 3.x). It has more or less the same functionality of the Arduino Duemilanove, but in a different package. It lacks only a DC power jack, and works with a Mini-B USB cable instead of a standard one.