Linda Sengpiel was the first female professional yo-yo demonstrator. In 1951, she began demonstrating professionally for both Duncan and Pedro Flores. During those early years, she was known as the "Yo-Yo Queen."
In the 1970's Linda was contracted by a large publishing company to package her own trick book with a yo-yo and other items for retail sale. A total of 100,000 units were ordered. However, once the pack had been produced, the contracting company's sales staff was reluctant to promote this new product. Apparently it was due to the large shelf space necessary to display the set, in combination with a low profit margin. The order was accepted, but before distribution could begin, the company shut down. The packs were held in a warehouse for a year before being returned to Sengpiel.
Shortly thereafter, an agreement was reached with Lawson, a food store chain, to release the Sengpiel Supersonic Yo-Yo Pack in the Northeast. A commercial promotion the pack was produced and aired during this period. The yo-yo kit was on an oversized blister card (16 X 11 1/2 inches) and included a Super Sonic Yo-yo, three membership cards, four pin back pins, two stickers, a Festival string pack and a trick book. The kit retailed for $2.98. A less common, smaller version of the kit was also packaged to cut down on shelf space. This small card version had a fixed price of $1.49 and contained a yo-yo, two pin back buttons, and a string pack.
Information taken from "Lucky's Collectors Guide to 20th Century yo-yos".