Scientific Anglers SA Indicator Marker is designed for direct marking of monofilament to create sighters or touch indicators used in fine fishing, particularly nymphing with wire. The product applies quickly, dries quickly and becomes water-resistant once in place, without color transfer. The marking remains very fine, without adding weight or volume, so there's no extra drag on the drift. Colors are visible in different light conditions, making it easy to read the line. The formula is heat-stable and can be removed with an alcohol wipe when marking is no longer required.