Prayer Wheel, Buddhist Mani Chos' Khor, in Buddhism, is a mechanical device that use of which is equivalent to the recitation of a mantra. The prayer wheel consists of a hollow copper cylinder, often beautifully embossed, mounted on a rod handle and containing a tightly wound scroll printed with mantra. Each turning of the wheel be hand is equivalent in efficacy to the prayer's oral recitation multiplied by the number of times that mantra is printed on the scroll.

Variants to the hand held ones, prayer wheels are larger cylinder that can be attached to windmills, or waterwheels, or in the temples.  the mantra on the prayer flags is similarly activated by the blowing of the wind.