The device features two dock connection ports, something that was rumored for the iPad 2. Unfortunately, the novelty of the two ports will be somewhat dampened by the fact that this iPad only runs a testing platform called Switchboard instead of iOS.
As the seller describes it:
This is one of a VERY small amount of Apple prototype devices and you rarely see these on ebay. This iPad has 16GBs of capacity, and is incredibly unique … Apple prototyped these iPads to have this connector late in the process and at the last minute decided to remove them. There are patent drawings and leaked casings that show the indents for both dock connector holes, but this unit has both dock connectors, and both are full functional for charging this iPad and connecting it to your computer.
There were certainly rumors to the effect that a new iPad would have two ports, and as the seller notes there were actually leaked cases and drawings that showed this design. This particular iPad, however, is the first actual device to show up with the ports intact.