PL007 is a .007 gauge plain steel string for acoustic or electric guitar. Perfect as a replacement string or for creating customized sets. D Addario plain steel guitar strings are acclaimed worldwide for their superb long-lasting tone. They are equally suitable for both electric and acoustic guitar. .009 gauge plain steel string for acoustic or electric guitar 5-pack Superb long-lasting tone Perfect as a replacement string or for creating customized sets Made in the U.S.A. for the highest quality and performance