The Ernie Ball EB2733 45-105 Cobalt Hybrid Slinky are a set of cobalt hybrid slinky bass guitar strings , that are medium gauge , longscale, roundwound, and feature gauges of .045-.065-.085-.105 . Engineered to maximise output and clarity, Ernie Ball Cobalt Slinky Guitar Strings are the latest innovation in string technology. Seeking to provide guitarists and bassists with a new voice, Cobalt strings provide an extended dynamic range, incredible harmonic response, increased low end, and crisp, clear highs. Cobalt provides a stronger magnetic relationship between pickups and strings than any other alloy previously available. Cobalt Slinkys are also soft and silky to the touch, making string bending a breeze.