YOUR MOST VERSATILE FLY-TYING TOOL - THE HARELINE KRYSTAL FLASH.This versatile and effective material can be used on hundreds of fly tying patterns. The twisted strands of reflective mylar have a deceptively scaly look. You can add strands for subtle flash or greater noticability. The Hareline Krystal Flash, effective with both fresh and saltwater flies, is a must-have material for any fly tier.