I'm mainly talking about The AC(Power) Adapter.What kind of adapter are you talking about? Network adapter? AC(Power) Adapter? Video cords?
As advised by the guy above, official Nintendo accessories have at least a Nintendo logo on them. (However many counterfeits may still do)I'm mainly talking about The AC(Power) Adapter.
Also, I wanna know how to spot fake Wii Network Adapter and Video Cord too.