Description: Fly tying bobbins are an essential tool of the fly tier. The bobbin holds your thread spool and maintains constant tension on the thread, helping you to make durable, proportional flies. The bobbin is the perfect thread-management tool. Whether you are using any vise, this bobbin will improve, simplify, and speed up your fly tying. Specification: Material: Stainless Steel + Brass Bobbins Length: approx.11cm / 4.3inch Thread Spool Length: approx. 3.5cm / 1.4inch Thread Spool Diameter: approx. 3cm / 1.2inch Package Includes: 1 Piece Fly Tying Bobbin Holder 1 Piece Thread Spool