Fly tying bead sizes are 2mm, 3.3mm and 4.6mm, and have 5 colors, each size/color 10 beads. This assortment contains total 150 tungsten beads. An assortment of tungsten beads with most widely used sizes and most productive colors for fly fishing. 97% tungsten with high quality coating ensures long term use. Tungsten has a higher density and smaller profile than brass or leads which means your fly will sink faster, and has a more natural action. Hole design fit your hook and your tying material better. Comes in a small utility box.