The Noodler's Ahab flex pen is crafted from a celluloid derivative with its profile inspired by the shape of Ahab's Great White Whale. The stainless steel nib is flexible ranging from a fine point to medium thickness with gentle finger pressure on the down-strokes. Larger in size than the Noodler's Nib Creeper Flex nib the Ahab measures 5.47 closed (capped) and 6.7 with cap posted. Fills via ink pump or can also be used as an eyedropper fill. Cannot use ink cartridges to fill.