Gauges 11-15-22-30-40-50. Pre-Alloy Phosphor Bronze Acoustic Guitar Strings are high-quality, long-lasting strings. Pre-Alloys are bright and unusually well-balanced in tone (first) and volume (second). Entirely all-American alloy phosphor bronze strings have great clarity and durability. Gauges 11-15-22-30-40-50 Bright, well-balanced tone and volume