Magna bolas

Magna bolas consisted of three heavy, metallic balls attached by a thin wire. They were twirled and thrown at a target, and if aimed correctly, their natural rotation entangled the target in the wire. The metal balls were then activated, producing a strong magnetic attraction which made the bolas nearly impossible to escape. Magna bolas were used as a capturing weapon by the more civilized bounty hunters.

Source

 * Coruscant and the Core Worlds