Diabolo

Chinese yo-yos old and new

The diabolo (/diːˈæbəloʊ/ dee-AB-ə-loh;^[1] commonly misspelled diablo) is a juggling or circus prop consisting of an axle (British English: bobbin) and two cups (hourglass/egg timer shaped) or discs derived from the Chinese yo-yo. This object is spun using a string attached to two hand sticks ("batons" or "wands"). A large variety of tricks is possible with the diabolo, including tosses, and various types of interaction with the sticks, string, and various parts of the user's body. Multiple diabolos can be spun on a single string.^[2]

Like the Western yo-yo (which has an independent origin), it maintains its spinning motion through a rotating effect based on conservation of angular momentum.