Fusion Matched is the trademarked proprietary method that combines the highest quality, 100% made in the USA wire & 100% USA workmanship to produce strings with exacting core to-wrap ratios & tolerances. Trebles are made from clear nylon filament and the bass strings are made by winding silver-plated copper wire onto nylon floss. Gauges: 90613 - Normal Tension Tie On 90611 - High Tension Tie On - 30-33-41-30w-37-44