"The original high performance finger harness." Company was a sponsor of the 1999 World Yo-Yo Competition in Honolulu, Hawaii.
Patent was filed February 22, 2000, thus the pending designation on the product. US patent 6247992 was eventually issued June 19, 2001 to William Higgins, III of Mayfield Heights, Ohio-- at the end of the last big yo-yo boom of the 20th century.
Their website was www.supersling.com which is no longer active (checked July 13, 2015).
Of interest... Over the years yo-yo makers have tried various methods to alleviate "Yo-Yo Finger" -- the pain caused by prolonged wear of a yo-yo string around your middle finger. Here are a few variations that have appeared on the market since the early 1980s:
