This RFID modules base on MFRC522 IC and that can read and write Mifare's tags. The microcontroller and card reader uses SPI for communication. The card reader and the tags communicate using a 13.56MHz electromagnetic field.The RFID MFRC522 module supports MF1xxS20, MF1xxS70 and MF1xxS50 tags. The RFID MFRC522 module supports contactless communication and uses MIFARE higher transfer speeds up to 848 kBd in both directions.RFID MFRC522 have a compact design and small size 36x36mm. Power can supply 3.3V or 5V. This easy for connection to board with 5V, not need power regulator for 3.3V.The antenna is built into the board. And it has a good sensitivity to a height of 25mm*tags not in the set.