Duncan yo-yo replacement strings for all Duncan yo-yos. Cellophane package of two 100% Egyptian cotton strings for ten cents. From around 1961.
This blue string package version is hard to find, especially in this condition. Most are found faded with rips or tears in the paper from being stapled, and the overall design of the two-color printing is usually misaligned. Compare with the Duncan red string package version from around 1963.