Scientific Anglers Stillwater SD Fly Line - Designed specifically for the demands of stillwater anglers. Overweighted by two line weights for multiple flies and long leaders. Features 10-foot and 20-foot textured hang markers. Seamless Density technology provides a smooth transition between densities, eliminates hinging, and provides a straight-line connection to the fly. Sonar sinking technology gets flies down, and keeps them there. Shooting Texture running line delivers longer casts. Sink 5/Sink 7: The fastest sinking SD line, with a Sink 5 running line and Sink 7 (7.0 ips) head, designed to dredge the bottom.