D'Addario Alto Guitar strings are made specifically for the nylon string Alto Guitar. The first 3 strings are clear nylon and the 3 bass strings are silverplated copper wound. Each D'Addario Pro Arte treble string is measured 200 times by a sophisticated computer comtrolled laser system that performs consistency and quality control checks while determining the strings exact playing tension.,,E - .029,B - .0333,G - .0416,D - .030,A - .036,E - .045