The module is a SD card read and write module; SCM system can read and write files in the SD card through SPI interface; Arduino users can initialize read and write card by using SD card library of Arduino IDE with this module. Feature : 1. Compatible with Arduino UNO Arduino MEGA2560 and or arduino compatible boards; 2. SD card(<=2G) SDHC card(<=32G) supportable; 3. On-board level conversion circuit that is the interface logic level can be 5V or 3.3V; 4. On-board 3V regulator circuit power supply can be 3.15V ~ 5.25V 3.3V/5V SCM system compatible; 5. Communication interface is standard SPI; 6. 4 M2 screw mounting holes easy to install.