Prayer wheel
A prayer wheel is a cylindrical wheel (Tibetan: འཁོར་ལོ།, Wylie: 'khor lo, Oirat: кюрдэ) on a spindle made from metal, wood, stone, leather, or coarse cotton, widely used in Tibet and areas where Tibetan culture is predominant.
Traditionally, a mantra is written in Ranjana script or Tibetan script, on the outside of the wheel. The mantra Om mani padme hum is most commonly used, but other mantras may be used as well.
Also sometimes depicted are dakinis, Protectors and very often the eight auspicious symbols (ashtamangala). At the core of the cylinder is a "life tree" often made of wood or metal with certain mantras written on or wrapped around it. Many thousands (or in the case of larger prayer wheels, millions) of mantras are then wrapped around this life tree.
According to the Tibetan Buddhist tradition based on the lineage texts regarding prayer wheels, spinning such a wheel will have much the same meritorious effect as orally reciting the prayers.