Steel Balls (鉄球 Tekkyū) are versatile weapons designed to facilitate the usage of Spin, featured in Steel Ball Run. In two types, they belong mainly to Gyro Zeppeli and Wekapipo. However, anyone proficient in the Spin is capable of using these weapons to similar effect, even if a spherical object is not their regular implement for accessing it.
The Zeppeli Family's Steel Balls are polished, highly spherical balls of steel, about the size of a baseball or boule. They are grooved on opposite faces by two large hexagons, almost joined by lines crossing the balls between their corners.
These Steel Balls are designed to facilitate a powerful and versatile form of Spin focused on the manipulation of human or animal anatomy and various organ systems. They may be thrown far and with force, and maintain a lengthy, regular Spin, able even to boomerang after impact to be caught by their user.
They are used originally by the executioners serving the royal family of Naples, handed down through the generations of the Zeppeli Family. The techniques of the Steel Ball were developed with the aim of finding an honorable method of execution that allows instant death, without regard to the condemned person's anatomy or resistance.
They have an effective range of around 20 to 30 meters.
The Scan ability (or the ability of the eyes of the Saint's Corpse) is shown to interact directly with Steel Balls, by placing an eye within them to allow the User to see through them.
Similar in size to the Zeppeli Family's Steel Balls, Wrecking Balls (レッキング・ボール(壊れゆく鉄球) Rekkingu Bōru (Kowareyuku Tekkyū)) are covered regularly by large dimples housing smaller balls, called satellites, which may separate in-flight to strike targets on their own. Even if these satellites do not quite meet their target, they produce airborne shockwaves which will induce an effect.
Wrecking Balls facilitate a form of Spin designed to induce temporary hemispatial neglectW (左半身失調 Hidarihanmi Shitchō, lit. left-half ataxia); effectively killing all sensation in the left side of a target, explained as the cause of the ball's impact traveling through the body to cause a stroke or hemorrhage in the motor cortexW.
The Wrecking Ball is primarily used by the guards serving the royal family of Naples.