prayer wheel 
noun
A small revolving cylinder inscribed with or containing prayers, a revolution of which symbolizes the repetition of a prayer, used by Tibetan Buddhists.Thus is the Tibetan prayer wheel the true emblem of belief as such....
- We'll just give it a spin now and the bell sounds on each revolution of the prayer wheel.
- They also believe you can produce the same effect by spinning the written form of the mantra around in a prayer wheel (called ‘Mani wheels’ by the Tibetans).