D'Addario EJ65B strings are designed specifically for baritone ukuleles. The 3rd and 4th string are a silver-plated copper wound on nylon and complimented by a 1st and 2nd Pro-Arté Custom Extruded clear nylon strings. Extruded Nylon strings are manufactured on D'Addario's own advanced monofilament extrusion line built exclusively for the production of musical instrument strings. Each set features their exclusive laser sorted Pro-Arté clear nylon trebles for unsurpassed intonation with a warm, projecting acoustic tone.