Klang resembles three interlocking gears, with six teeth on the smaller two gears and eight teeth on the larger gear. The teeth of the smaller gears are a light gray, while their central regions are much darker. The teeth of the larger gear are a medium gray and its central region is darker. The left eye of the smaller gear is a white "X", while its right eye has a black pupil and a white sclera. It has a round green nose and a small mouth that is wide open. The large gear appears to have a face with a black square for its left eye, a black circle for its right eye, and a sharply angled white frown. Klang can fire tiny gears at high speeds in the form of Gear Grind and Shift Gear, its signature moves. When it gets angry, its gears rotate faster. Klang communicate with each other by spinning their gears in different directions.
Klang debuted in White—Victini and Zekrom and Black—Victini and Reshiram alongside Klink and Klinklang; they are all under the ownership of Mannes. He used the three for various tasks, such as powering the music machine at Eindoak Town's Harvest Festival, doing yard work on his property, and powering his helicopter in the climax of the films.
Klang is based on interlocking gears, more specifically the sun and planet gears. The Klink line's Shiny coloration may have been based on copper gears, as their noses have turned green as copper does when it oxidizes into such compounds as copper carbonate, forming a patina.
Klang is a corruption of clang (onomatopoeia for heavy metal striking a surface).
Gigiaru is derived from gear, with gi repeated once to denote the addition of Klang's third gear.