This is a Micro SD(TF) module from DFRobot. It is compatible with TF SD card (commonly used in Mobile Phone) which is the most tiny card in the market. SD module has various applications such as data logger, audio, video, graphics. This module will greatly expand the capbility an Arduino can do with their poor limited memory. 

This module has SPI interface and 5V power supply which is compatible with Arduino UNO/Mega.   The Pinout is fully compatiblw with DFRobot's IO Expansion Shield V7.