Ernie Ball Extra Slinky Flatwound Bass Strings combine the silky feel of traditional flats with the power of Cobalt. Cobalt strings are made with a modern alloy formulation that attracts the magnets in your pickups better than other alloys, delivering higher output, better sound, and longer string life. Featuring a SuperBright Cobalt ribbon wrap, Cobalt under-wrap, and an optimized hex-core/wrap ratio, Ernie Ball Slinky Flatwound bass strings combine the smooth feel of flats with the growl and brightness of rounds. Bassists at String Swap love Ernie Ball Slinky Flatwound Bass Strings. We’re confident you will too.