The Evolution Caddis tungsten bead is designed with the right size, proportion, shape and colors. Caddis typically have a small head attached to a large body and this distinct proportion between head size and body size is very important for fly tiers to imitate (and not possible to achieve with standard round beads). The Evolution Caddis tungsten bead solves this fundamental problem by allowing a smaller size bead to fit onto a larger hook size in order to get the correct small head/large body ratio and profile. It mimics that of a typical caddis pupa which has a round, undersized head with round, bulbous eyes. In addition, the bead is designed in such a way that on the hook it tilts forward and looks downward to imitate the typical “head arched down on a curved body” caddis pupa profile.