I believe this is the second string pack issued by Hummingbird Toy Company. (Compare with its first issued pack.)
The back of the pack was sealed with tape.
Any Hummingbird string packs are fairly hard to find. Hummingbird Toy Company went out of business near the mid-1990s. Many of their old yo-yos are prized collectibles today (2006).
Made by the Hummingbird Toy Company, Ltd., 32 Water Street, P.O. Box 276, Arcade, New York 14009
