This Ethernet Shield gives you an easy way to get your Arduino Online. It is directly supported by For Arduino official Ethernet Library. It adds a micro-SD card slot, which can be used to store files for serving over the network. It is compatible with Arduino Duemilanove (168 or 328), Uno as well as Mega (1280/2560) and can be accessed using the SD library. It supports up to four simultaneous socket connections.