With this nice ergonomic nib holder, you have very nice control over the pen when writing. Your fingers stay in the right position when writing through the recess in the wood. It's nice that your fingers don't automatically move while writing. The wood has been coated several times and can therefore withstand the ink.
You attach the nib in the metal opening, which you can adjust for all nibs. You can do this very easily. For this, you use the 'top' (not sharp side) of a somewhat larger nib; you press the metal flanges inwards as far as necessary for your nib.