The EJ99SC Soprano/Concert Ukulele Set consistsof all-nylon strings made from D'Addario's exclusive Pro-Arté Carbonstrings. This fluorocarbon set is optimized for usage with standardGCEA tuning. Pro-Arté Carbon Ukulele strings are designed for theperfect blend of tone and projection. These fluorocarbon sets are idealfor progressive ukulele players looking for a bright, modern sound.