Martin M600 Soprano Uke A small but mighty sound. Martin Ukulele strings offer a high tensile strength core wire to hold tunings longer and improve harmonic output for consistent true tone. Martin Ukulele strings are made with clear fluorocarbon, aluminum wrap on nylon and tin plated copper on nylon. Soprano/Concert .0191 .0256 .0340 .0216 - - 30 M600 • MFSKU M600 • UPC 729789106009