ZEBRA Electric-Acoustic strings are made for acoustic-electric guitars with piezo pickups under the bridge or magnetic pickups in the soundhole. Also for full size archtop jazz guitars, which respond to Zebras with richer tones, according to players. Any amplified acoustic comes alive when you put on the Zebra strings. A revolutionary string where you can see the difference. Other coils are nickel-plated steel, and other coils RARE phosphor bronze.