Tungsten is the material most commonly used for the barrels of professional steel-tip darts.
Tungsten is exceptionally dense, allowing manufacturers to make a slim barrel with substantial mass. A slimmer dart can reduce the amount of space it occupies in the target area, which is useful when a player is grouping darts tightly in high-scoring treble segments.
Professional darts are often described by tungsten percentage, such as 80%, 90%, or 95%. That figure refers to the tungsten alloy content of the barrel, not to the complete dart. The remaining material may include nickel, iron, or other alloying elements.
Brass barrels are common in inexpensive recreational darts because brass is cheaper and easier to machine, but they are generally bulkier for the same weight. Tungsten does not automatically make a player better; grip design, balance, and technique also matter.