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 Strings sound and feel better than anything I've ever played! You have to check these out!" - Slash. "Cobalt Strings feel incredibly silky under my fingers and deliver more punch, output, and clarity than normal strings!" - John Petrucci. 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.