Silver plated copper wound on an exclusive Composite core material for powerful, long lasting tone / Wound strings are polished to a smooth surface for reduced finger noise, great for recording! / Exclusive multifilament core material / Made in the U.S.A. for the highest quality and performance / String Gauges: Trebles .0290, .0333, .0416 Basses .030, .036, .045 / Environmentally friendly, corrosion resistant packaging for strings that are always fresh