The #18 tips, all unique to Razertip, are probably the most versatile tips in the history of pyrography. They can all be used for fine feather and hair detail, "carving" feathers and quills. They can also be used for scaling, shading, and calligraphy. They are the only pen that can simulate "stoning" effects as well as "rippling" on feathers. Their unique shape makes them very tough and durable. Model #18M