This is an internal airport card for the MacBook and MacBook Pro, Core 2 Duo model with 802.11.g/n. This card will work for older MacBook models but will not necessarily support 802.11n. Check out the compatibility tab for a full list of compatible machines.
With some of the 802.11n Airport cards, there were three antenna connections; others had only two. Both support N wireless networking. If you receive a card that only has two connections and you have three antenna connections, you should only have to connect the black and gray connections for it to work.