The most popular Slinkys with a Cobalt twist. "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. "There's a certain degree of clarity and punch you get from Cobalt Strings that I haven't heard tonally from any other strings I've played." - Joe Bonamassa. 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.