Bought this for bird photography but hardly ever used it (didn't take any pictures of birds!) so that's why I'm selling. It reduces the maximum aperture by 2 stops of any lens it's mounted on.
Nikon has compatibility charts for the lenses that this teleconverter works with. For example, some lenses can't be used with it because the lens elements hit one another, other lenses can be used but autofocus doesn't work. So it's best to check the compatibility charts. before buying.