Ernie Ball 2733 Cobalt Hybrid Slinky Bass Strings are round-wound for maximum clarity and serious punch. Featuring a combination of Super Slinky and Regular Slinky gauges, the Cobalt Hybrid Slinky set 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.