Pen Holders are simply a wooden body that accepts the pen (nib) and allows you to grip it and maintain control while drawing.
Mapping Pen Holder has a smaller opening and will only hold the Mapping Pen Nib.
Wooden Pen Holder (N20) has a larger opening and will hold the School, Spoon and G pen nibs, but not the Mapping pen nib.
Free Size Pen Holder features special double rubber rings at the tip, the inside ring will accept the Mapping Pen Nib, and the outer ring will accept the School, Spoon and G pen nibs. The Free Size Pen Holder is available in white or pink.