W5100 Ethernet Shield Module Micro SD Card Slot for Arduino UNO MEGA Main features: ● It is directly supported by 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 the Arduino duemilanove (168 or 328), UNO as well as Mega (1280 / 2560) and can be accessed by using the SD library. ● The wiznet W5100 provides a network (IP) stack capable of both TCP and UDP. ● It supports up to four simultaneous socket connections.