The MFRC522 is a highly integrated reader/writer IC for contactless communication at 13.56 MHz.
Features:
MFRC522 chip based board
Operating frequency: 13.56MHz
Supply Voltage: 3.3V
Current: 13-26mA
Read Range: Approx 3cm with supplied card and fob
SPI Interface
Max Data Transfer Rate: 10Mbit / s
Dimensions: 60mm × 39mm
 
Communicating with an RC522 RFID module is a lot of work, but luckily for us there is an Arduino library called the MFRC522 library that makes reading and writing RFID tags simple.