There are very few companies in the world that make their own Fluorocarbon resin; likewise there are very few companies in the world who extrude their own Fluorocarbon resins. Seaguar is the ONLY brand on the market that does both! Seaguar operates and controls the Fluorocarbon manufacturing process entirely from beginning to end, for 100% quality control. ALL other brands on the market are forced to rely on outside sources for extrusion or resins, leaving quality control to a third party. Several of our competitors do not take part in the production process at all, handling only the marketing aspect of their Flourocarbon Line and Leader. Seaguar invented Fluorocarbon Leaders and Line in 1971 and has been progressing and improving upon the process ever since. Only Seaguar offers Leaders with Double Structure Technology (DST). DST Leaders are comprised of two different resins, both of which are 100% Seaguar Fluorocarbon. The core resin is harder for improved tensile strength, and the 2nd resin is softer for greater knot strength. Although the product is comprised of a core resin and a 2nd resin, the line is not wrapped or coated, the end result of Seaguar's patented manufacturing process is one solid piece of 100% Seaguar Fluorocarbon, impossible to separate, unmatched in its innovation, design and performance.