The Ernie Ball Regular Slinky 5-String Flatwound Electric 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 flat wound bass strings are the first flat that actually feels like a flat and sounds like around. Gauges .045, .065, .080, .100 .130.