This Arduino-sized Ethernet Shield is based on the Wiznet W5200 Ethernet Chip, and provides an easy way of getting your Arduino Online. Fits all version of arduino Main board,e.g.UNO, mega 2560. To start, just plug this module onto your Arduino board, connect it to your network with an CAT 5 Ethernet Cable (not included) and follow a few simple instructions, you will be able to explore the world with internet. The pin layout also allows another shield to be stacked on top. An aluminum alloy radiator is placed onto W5200 chip to release excessive heat.