WE HAVE CHECKED ALL THE COMBINATIONS OF NIBS AND PEN HOLDERS PERSONALLY,
SO YOU MIGHT REST ASSURED THAT THE CHOSEN SET CAN BE USED PROPERLY.
If we say that a nib fits the pen holder, it means that the nib will be held in proper position while writing. If it's stated that a nib does not match a specific pen holder, it means that due to the shape or design, the nib cannot be put in the pen holder or will be hold improperly (e.g. too loose or too shallow).