Mobius & Ruppert - Brass Round Double-Hole Pencil Sharpener -The unique two hole style is a distinctive emblem of taste for discerning creative people. It is ideal for all pencils in the artist s sketch box including large diameter art pencils. The small hole (7.8mm) is for a standard pencil diameter and point taper. The large hole (11mm) is perfect for careful sharpening of charcoal, pastels and colored pencils. To assure a good cut, blades should be changed often. The replacement blade is MG100-0050.