Designed specifically for Requinto guitars and tuning / Rectified clear nylon and silver-plated copper wound on nylon strings / Warm and projecting, long lasting tone / Made in the U.S.A. for the highest quality and performance / String Gauges: Clear Nylon: .022, .028, .033, Silver-plated Copper: .025, .030, .036 / Environmentally friendly, corrosion resistant packaging for strings that are always fresh