The nunchaku is a traditional Okinawan martial arts weapon consisting of two sticks connected at one end by a short chain or rope. Used by Okinawan nobles, it was not a historically popular weapon because it was ineffective against the most widely used weapons of that time, and because few techniques for its use existed. The two sections of the weapon are commonly made out of wood, while the link is a cord or a metal chain. The nunchaku is most widely used in martial arts such as Okinawan kobudō and karate, and is used as a training weapon, since it allows the development of quicker hand movements and improves posture. Many varieties of nunchaku are available.
In modern times, nunchaku (Tabak-Toyok) were popularized by actor and martial artist Bruce Lee and his student, actor and martial arts instructor Dan Inosanto, in their respective movies. Organizations including the North American Nunchaku Association, World Amateur Nunchaku Organization, Fédération Internationale de Nunchaku de Combat et Artistique, World Nunchaku Association, and International Techdo Nunchaku Association teach the use of nunchaku as a contact sport.
Modern-day nunchaku can be made from metal, wood, plastic or fibreglass. Toy and replica versions made of polystyrene foam or plastic are also available. Possession of this weapon is illegal in some countries, except for use in professional martial art schools.
Ref : https://en.wikipedia.org/wiki/Nunchaku