Copper, colored wire in a flat design. Size Medium is ideal for use with sizes 10 - 16 hooks. The advantage of these wires over synthetic materials is primarily their strength. They easily withstand fish teeth, ensuring that fish won't ruin our successful lure, which might be the last one in the box. We can use these wires for making ringings, for entire bodies, or to reinforce flies or attach some materials, such as feathers, to the body of the fly.