As extra fine as you would expect!
"This is my first Pilot pen and first try of the EF nib. As its a JP pen, extra fine is super super fine, compared with say, the EF in the Waterman FP. I ground down this one VERY slightly as I wanted it between an F and EF, so if you want a fine line but don't want it so fine that the pen is virtually a drawing tool (and don't want to grind it), I suggest the F is for you.
I am new to Pilot Namiki pens and was very pleased that the nib is quite robust and survived the post very well (some nibs are sensitive to a slight knock) and it came very quickly via USPS.
Will definitely use Anderson Pens again!!