The Ernie Ball M-Steel strings are the loudest and most expressive strings ever made. They deliver higher output, resonance, response, and strength. M-Steel stands for maraging steel, a high-strength and very tough steel used in applications such as aerospace and in blades and knives.

The wound strings are made from hexagonal maraging steel wire, wrapped with cobalt wire. This produces a fat, powerful tone with appealing low-end. The plain strings are made from specially hardened steel, making them more durable and resistant to fatigue. Additionally, the ball end is extra wrapped to prevent breakage at that point and to help the strings stay in tune longer.