Ernie Ball Slinky Flatwound Bass Strings combine the smooth feel of traditional flats and the power of Cobalt. Featuring a Super Bright cobalt ribbon wrap, Cobalt under wraps 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: 0.045, 0.065, 0.085, 0.105.