Faber-Castell E-motion Fountain Pen Spare nib are available in four different nib sizes.
Medium, Broad, Fine and Extra Fine.
Emotion Series nibs are provided with the housing attached and you may unscrew the section to replace the nib.
The E-motion series has a wider Grip section while the Ambition has the slim Grip section.
Both nib and it's housing (feed) can be unscrewed.