ORTEGA Authentic, Select, and Pro strings are made with exclusive winding and polishing techniques. Our superior materials are globally sourced and produce a traditional rich, warm sound with a distinctive bright timbre. String sets for nylon-string guitar, acoustic bass, mandolin, banjo, ukulele, and guitarlele are included in the comprehensive collection. The anti-rust coating on the Pro and Select sets prevents tarnishing and preserves the clear tone of new strings .026, .031, .038, .027w, .033w, .040w