Do NOT purchase that. Its a Wii accessory designed to trick Wii U owners with the look.
It only functions as a wiimote or a wiimote+classic controller and its poor quality even in those categories.
It does NOT work as a Wii U pro controller. Its pretty though.
It's not a WiiU Pro Controller at all, so you won't be able to play Wind Waker, ZombiU multiplayer, etc.
I guess it might be a good substitute for a Classic Controller for your original Wii, since it's completely wireless (no need to attach to a Wii remote) but the build quality is probably crap (reviews kinda say this).