The Ernie Ball Hybrid Slinky Cobalt Flatwound 45-105 Gauge strings are a bass guitar string set that combines the smooth feel of traditional flatwound strings with the powerful output and clarity of cobalt alloy. They feature a SuperBright Cobalt ribbon wrap, underwraps, and an optimized core-to-wrap ratio for comfortable playability and a versatile tone that aims to sound like a roundwound but feel like a flatwound. The set includes gauges of .045, .065, .085, and .105.