Description Ziller Ink Thickener is a clear liquid that can be added to all other Ziller dip pen ink colors except for the Glossy Black Powder, to thicken the ink. Add a drop or 2 at a time and stir, to reach your desired consistency. The 1oz glass bottle has a square base which keeps it stable while open and in use. Ziller dip pen ink is for use with for dip pens ONLY. DO NOT use with fountain pens, as it can permanently clog them. We offer Free Shipping on all orders over $50 for US customers, and for orders over $250 for our Canadian customers.