Krystal Flash is comprised of fine strands of reflective mylar that are twisted, giving the flash an intermittent ''scaly'' look. This effective material is used on virtually hundreds of fly tying patterns, and for good reason. Add a couple strands for a subtle flash or tie in even more for greater noticeability. Krystal Flash is great for both fresh and saltwater flies and is a must-have material for all fly tiers.