This pack of Medium Light Aluminum Bronze Strings from Ernie Ball is intended for use with six-string acoustic guitars. Their core is fashioned out of hex-shaped maraging steel wire which is wrapped with a proprietary aluminum bronze alloy wire. As such, they help engender a coupling of pronounced lows and clarion highs, providing more projection and clarity than traditional bronze strings, as well as an improved resistance to corrosion. All Ernie Ball strings are hermetically sealed to ensure freshness.