Ernie Ball 2731 Cobalt Power Slinky Electric Bass Strings are round-wound for maximum clarity and serious punch. The Cobalt Series is clearly an improvement on its classic nickel-wound counterpart giving the player increased sustain, clarity and output. In addition, they resist sweat and moisture better and have unmatched flexibility when compared to other nickel wound strings. "Ernie Ball Cobalt Bass Strings are the new standard! Bigger, better tone, sustain and volume. Finally a real innovation with strings." - Randy Jackson "I can"t believe how much low end I get out of Ernie Ball Cobalt Bass Strings. Also, the high end is super crisp, seemingly with more definition. Unbelievable." - Dave Larue All Ernie Ball strings are precision manufactured to the highest standards and the most exacting specs to assure consistency, optimum performance and long life. Made in the USA. Gauges 55-75-90-110.