Engineered to maximize output and clarity, Ernie Ball Cobalt Slinky 7-string guitar string sets are one of the latest innovations in string technology. Seeking to provide guitarists and bassists with a new voice, Cobalt strings provide an extended dynamic range, incredible harmonic response, increased low end, and crisp, clear highs. Cobalt provides a stronger magnetic relationship between pickups and strings than any other alloy previously available.