Ultimate flexibility, this is a cut above your standard flex nib. This is a professional grade nib so please make sure you understand your purchase by reading the DETAILS section before ordering. My Pro-Flex Nib (PATENT PENDING) has been designed from the ground up and has a few novel features which separate it from the your standard flex nib: The Pro-Flex is fitted with a Titanium Coated Zebra G calligraphy nib, this is the cream of the crop when it comes to calligraphy nibs and gives you the finest of fine strokes and the juiciest of thicker strokes. It's perfect for drawing, calligraphy and just putting pen to paper. It flexes from hairline to 2mm.