Roto Greys use a highly secretive core to cover ratio in their making and offers such brilliant sustain and tonal nuances few others can equal. The longer European eye adds extra strength at the ballend so a more durable string! Roto's unsurpassed quality and constant care to detail results in a string equally geared to the professional and novice alike. All Rotosound strings are manufactured in England and recently celebrated 50 years of productioin! In stock now at Twin Town Guitars! • MFSKU R-13 • UPC 686194000547