Nintendo has finally made the Circle Pad Pro attachment for the 3DS XL available… and only via their ShopNintendo online store. The Circle Pad for the standard 3DS was a GameStop and Nintendo Store exclusive. Used for the likes of Resident Evil Revelations, Kid Icarus, and Monster Hunter, the bulky piece clips onto the hardware to offer a second analog stick.
For some time, the standard Circle Pad was a tough find. GameStop and Nintendo both sold out, letting the bulk of sales go to eBay resellers. The accessory shot up to $50 and hovered there until they landed in stock again, bringing prices down to Earth-sensible levels. Retail price is $20, although you’ll also need to pay shipping when buying from Nintendo, so plan for other $5 (plus sales tax where applicable). Also, a couple of AAA batteries would not hurt either: It needs one to function.
Source: Joystiq