McFly Foam is a strong, stretchy, continuous filament yarn which is dyed using colorfast dyes that prevent it from fading. Use it to tie eggs, glo bugs, and sculpted patterns like sculpins, crab patterns, and woolhead flies. McFly Foam is widely regarded as the best yarn for creating perfectly round eggs and is very easy to work with and blend. If you're looking for the best fly tying material to tie beautiful egg patterns with efficiency and ease, look no further. This stuff flat out catches fish and is available 49 beautiful colors!