I bought it online, along with others. It works for the Nintendo DS. Actually, I have it in several colors even. My kids keep misplacing the stylus. So I simply bought a few extra to have them on hand.
If you want to proclaim it to be a fake, that is your choice. I can only attest to the fact that it does indeed work with the DS and fits inside of it like the original.
I have three pink stylus with a clear tip and one black with a white tip. The last one is white with a white tip. This auction is for one only (just in case anyone is wondering). You may pick the one you want though :) .