The set includes 5 calligraphic nibs in different sizes (0,70mm, 1.00mm, 1.50mm, 2.00mm, 2.50mm), so that one can write special invitations in Gothic style letters. The converter replaces the fountain pen cartridges, and can be inserted in the rear part of the ferrule, with a slight pressure. Before sucking up the ink make sure the converter is secure. Turn the black plastic part clockwise, bring down the plunger at the bottom of the converter. Then, insert the tip of the pen into the ink bottle, and turn the black plastic part clockwise to fill the converter, remove the tip from the bottle and dry with paper towels. Plastic nib and Iridium tip material.