Duncan – The Original and the World’s No.1 Yo-Yo. Duncan has become synonymous with the yo-yo, as our yo-yo’s are the finest in the world and have been since 1929. From the beginner player to World Champion, our products cater to all skill levels and styles of play. For 84 years Duncan has produced high quality, world renowned products that have more play value than any other. With products ranging from world famous yo-yo’s and spin tops to juggling products, our entire line of skill toy products promote physical activity, build motor skills, enhance hand-eye coordination and provide endless fun for all ages.