Butterfly swords, not to be confused with balisong/butterfly knives, are short swords originating from southern China. It is popularly associated with the martial art of wing chun. Its short length allows for easy concealment and allows greater during close-quarter combat. Butterfly swords are usually wielded in pairs. A pair of swords will often be carried side by side within the same scabbard, so as to give the appearance of a single weapon.
The butterfly sword has a small cross guard to protect the hands of the wielder, similar to that of a sai, which can also be used to block or hook an opponent's weapon. In some versions, the crossguard is enlarged offering a second handhold, held in this position the swords can be manipulated in a manner akin to a pair of tonfa. They may also be used as brass knuckles when non-lethal application of the weapon is desired.
-- From Wikipedia
Fire and Steel butterfly swords are sold as a pair. Carbon steel. 53.3 cm length. Comes with a nylon sheath.