Brass knuckles, also sometimes called knuckles, knucks, brass knucks, B-Nux or knuckle dusters, are weapons used in hand-to-hand combat. "Brass" knuckles are pieces of metal, usually steel despite their name, shaped to fit around the knuckles. Designed to deliver the force of punches through a smaller and harder contact area, they result in greater tissue disruption and increased likelihood of fracturing the victim's bones on impact. Also, the wielder of such a weapon may punch harder than normal, exacerbating damage even further, due to reduced anxiety about harming their own hands when striking.
The Roman caestus was a type of glove or hand guard made from leather and metal used during boxing matches in gladiatorial events. Although modern day boxing gloves are used to keep the hands safe, thereby allowing the fighter to punch harder, the caestus was used solely to intensify the damage caused by a punch.
Vajra Mushti (Diamond Fist or Thunderbolt Fist) was the name of both a knuckle duster weapon and an ancient Indian martial arts identified with that weapon that incorporates striking and grappling aspects, and a study of vital points. The bagh nakh or "tiger claw" is a similar Indian weapon meant to be worn over the knuckles, although it is a slashing rather than bludgeoning device.
Knuckle dusters were incorporated into the so-called Apache revolvers used by criminals in France in the early 1900s. During World War I and World War II, trench knives, blades with enlarged guards to be used as knuckle dusters, were used in hand-to-hand combat in trench raiding operations.
In most countries, the possession, let alone use, of brass knuckles is illegal. Recently, brass knuckles have been sold on the Internet and in regular shops as novelties, although whether or not they are used as novelties is open to debate.
Brass knuckles can normally be purchased at flea markets, swap meets, and some sword and weapon shops. Due to a shady reputation they are often sold as paperweights or affixed with a detachable screw allowing them to be sold as a belt buckle.
Similar devices that are made of hardened plastic, rather than metal, exist. Some are marketed as "undetectable by airport metal detectors.
Due to the questionable legality of brass knuckles, large, heavy rings are sometimes used to achieve a similar effect.
In France, purchase and possession of brass knuckles is legal for 16 year-olds with parental permission, and are freely sold to people of legal age. They are sold as self-defense weapons.
In Canada, brass knuckles or any similar devices are listed as prohibited weapons, and possession of such weapon is a criminal offence under the Criminal Code of Canada.
Common varieties are spiked knuckles,"maiden's fingers", "fat boys", "wedding rings", brass knuckles with various "imprintable" images on the knuckles (longhorn steer, lions, skulls, etc), and even "knuckle-knives."
Spiked knuckles are seen to be of the most vicious variety of brass knuckles as they not only can shatter bone into fragments but will shred tissue. The length of the spikes varies from as small as a quarter of an inch to up to six inches. Shorter spikes emphasise the impact of the brass knuckle on bone, while longer blades are used solely to inflict soft-tissue damage.