The Terra Fly Tying Bobbins are an economical alternative to some of the pricier fly tying bobbins. Economical, however, does not mean 'cheap' when it comes to quality. The Deluxe Ceramic model features an extremely durable ceramic tip that is resistant to grooving. The Deluxe Ceramic bobbin is a great choice for all sizes of thread, including kevlar. The Deluxe Ceramic model measures 4 inches in length.The Standard w/ H.D. Tube model is great for holding larger denier thread. This model features a larger tube, making it a breeze to clean out excess thread wax build up. The larger size of this bobbin is also well suited for larger hands. The Standard w/ H.D. Tube model measures 4 1/2 inches in length.