Optimized for Soprano Ukuleles tuned to standard G-C-E-A tuning / Black precision rectified nylon ensuring that the roundness and dimension control of each string are unsurpassed / Preferred for their warm and long lasting tone / Soprano Ukulele, Rectified Black Nylon, Non-Ball End / Made in the U.S.A. for the highest quality and performance / Environmentally friendly, corrosion resistant packaging for strings that are always fresh