Gunbai

A or  is a non-folding fan, usually made of wood. It was used in ancient Japan by samurai officers to communicate with their troops. Nowadays, it is used by referees of professional sumō matches.

Madara Uchiha and Tobi have been seen wielding a large gunbai, about ¾ of their height and almost of their width, with the pole being twice that length. Madara's had a chain attached to the handle that appears to have been connected to his kama,   whereas Tobi's chain appears to enter his sleeve.

Tobi's gunbai, which he is able to guide with the attached chain, can be used as a shield and was able to block a Rasengan from Naruto Uzumaki while in his Nine-Tails Chakra Mode without receiving any noticeable damage. The edges of the gunbai itself also seem to be very sharp witnessed through Tobi using it to cut through rock.

Trivia

 * In the anime cut-scene of Naruto Shippūden: Ultimate Ninja Storm Generations, Madara is seen using his gunbai to create powerful gusts of wind, capable of blocking projectiles and blowing enemies away, as well as a melee weapon in combination with his kama.