It looks like a feather and can be wound like a hackle once the core is removed. You can slide the hackle up the core to make it denser for use as a bucktail. If you want a wavy tail, slide the core down leaving a portion of the core still inside. For an 8-inch fly, cut the feather to about 8 inches, hold the tip and slide the core down approximately 1 ½"-2". This section will then be floppy. Tie the butt end of the remaining length in, and make sure you tie the core and the hackle fibers to the hook shank. You can also bend the section that still has a core in it in almost any direction which makes the fly swim differently. Each package comes with 4 pieces, each approximately 14" long.