FENDER® BASS STRINGS 45-100Fender 7250ML Super Bass Medium Strings, The "high-octane" nickel-plated steel string for your bass. With a pure steel wrap, the magnets in your pickups use the whole string (not just the core) and transform the energy into high output bursts of sound. The nickel plating enhances feel and reduces "string squeak" and fret wear without compromising tone.