C&F Design Small 6-Row Fly Box with Midge Size Threaders. This threader fly box is for fly sizes from #26 and larger and as light as 7x and 8x. Six rows of Micro Slit Foam in the base hold up to 138 flies, while the lid contains a unique holder for six fly threaders and a white background for seeing hook eyes. The box includes six midge-size, pink dot fly threaders. Spare threaders are available separately.