A few years ago, a Nintendo Wii rip-off, called the Vii, appeared in China. A couple of Chinese dudes purchased one and then filmed themselves opening it up to see what was inside. There was a tiny, sole circuit board. They broke out laughing.
The inside of the Nintendo 3DS Circle Pad Pro, that add-on second circle pad, isn't that bad, but as this teardown shows, there sure isn't much inside that thing. It makes me wonder why they couldn't make the damn thing smaller -- not to mention do a better job of hiding the clearly visible screws.
The Nintendo 3DS Circle Pad Pro is available in Japan.
Check out Kotaku's impressions here.