Krenik Flash in a Tube
Flash materials have definitely changed the face of fly-tying as we know it. You can incorporate in into nearly any kind of fly pattern. I use it on nearly all my streamers, you can rib nymphs with it, or make a whole body on a Lightning Bug style nymph. You can rib beetles with it, or make a post for parachute dry flies, making a built-in strike indicator. Flies such as the Kraft's Kreelex are made entirely out of Krenik flash. The material itself is really a great all around material, but the packaging is really innovative. Conventional flash will get curled up and just generally gnarly from static electricity and rubbing on other materials, and more or less rendering it useless. Krenik Flash comes in a tube, which you pull the flash into with a zip tie when you're not using it, which prolongs the life of the material indefinitely. It comes in dozens of different colors and a couple textures, including a flat holographic version, and a “crinkled” version that looks great on any streamer pattern or dry fly wing. It's a very versatile, all around material, and is well worth having in your fly tying arsenal.