Ernie Ball 2813EB Hybrid Slinky Flatwound Bass Strings 45-105Ernie Ball Slinky Flatwound Bass Strings combine the smooth feel of traditional flats and the power of Cobalt. Featuring a SuperBright Cobalt ribbon wrap, Cobalt underwraps and optimal hex core to wrap ratio, the new Flatwound bass strings are the first flat that actually feels like a flat and sounds like a round. Gauges . 045, . 065, . 085, . 105