Fly Tying Material ② Thermo-Web 3-piece set Please check the image for colors. Thermo-web is a material with moderate stiffness that creates a shimmer in the water like seal fur, making it stand out underwater. The stiffness reduces the sinking of the tail when the fly stops during retrieval. It seems to be used as a substitute for hard-to-obtain seal fur. It is made of a new material that does not become cotton-like even when wet. It is highly lustrous and ideal for the bodies of wets, nymphs, tubes, and salmon flies. Thank you.