3DS Circle Pad Pro
The Circle Pad Pro features a second slider pad and three shoulder buttons, used to give the 3DS a more controller-like grip, and to make games such as RPGs or third person shooters more similar to those on consoles control-wise. The accessory requires one AAA battery to run, though one is only included with the original sized Circle Pad Pro. Its battery life lasts for 480 hours (20 days). It is also region free, which means one can use a Circle Pad Pro from another region of the world and it will still work on their 3DS, regardless of region of the system they are using.