Elixir® Attune Acoustic Phosphor Bronze Strings provide clarity to your acoustic stylings , an incredibly natural feel, and the longest-lasting tone of any string today— powered by a proprietary technology that delivers a difference you can hardly feel, but you can clearly hear. Experience the the firm grip putting you in control of bends and vibrato, while also withstanding the most hard-hitting attacks. Medium Gauge: .013, .017, .026, .035, .045, .056.