Dr. Slick fly tying tools have a reputation for excellence, and their Ceramic Bobbins are no exception. The Delrin feet keep even tension on the thread spool, and the ceramic inserts allow smooth application of thread to your fly. The inserts are funnel shaped, which keeps the thread from breaking and the tension smooth and even as the bobbin is rotated. Like every Dr. Slick fly tying tool, each Ceramic Bobbin undergoes a six-step inspection and is backed by Dr. Slick's lifetime guarantee. Available in 3 inch, 4 inch, and 4.75 inch sizes. Stainless steel and brass finish Dual ceramic inserts Delrin feet .