The Arduino Ethernet is the same shape as the normal Arduino Uno, with headers to connect wires or shields. However, the Ethernet jack is a little taller than USB so if you want to plug in a shield, you may need to 'lift' it with some stacking headers. Another thing to watch for is this Arduino does not have a USB port on it. Instead, you'll need an FTDI friend or FTDI cable to program it. There's a 6-pin connector that the cable plugs right into next to the microSD card holder.