Nintendo has added the 3DS XL Circle Pad Pro to their online store, the accessory is now officially available for pre-order before it ships April 19 for $19.99.
Originally released in Japan in November last year, the accessory adds a second analog stick to the 3DS XL console. The original 3DS handheld also had an attachment of this nature, but it was built for the smaller handheld specifically.
Though only a handful of games support this attachment, those being Resident Evil: Revelations, Metal Gear Solid 3D Snake Eater, Monster Hunter 3 Ultimate and Kingdom Hearts 3D: Dream Drop Distance. We would put our money on more titles including the Circle Pad Pro in the future.