It consists of Chinese explosives, disguised as a ruby, and powerful enough to blow up a city. Centuries later, a munitions expert found the Cufflink of Cathay and brought it to the USA. It was later disguised as a pair of cufflinks, which later disappeared into the private collection of Pietro Calzoni.
Krang and Shredder later wanted the cufflink, in order to blow the Technodrome free from the Volcanic Asteroid. To this end, they hired Big Louie to steal all the cufflinks in New York, leading to the Turtles becoming involved with the bizarre crime wave. Shredder eventually got his hands on the explosive cufflink by accident, but believed he had been tricked and tossed it aside.