Consider the Tibetan prayer wheel, a mechanical device that has a mantra or sutra passage encoded on it. Reciting the mantra orally is meritorious. Spinning a wheel with that mantra encoded on it carries the same merit but may be more efficient or accessible — for instance, an illiterate person who cannot read a sutra can still spin a wheel encoded with it.
Consider the Tibetan prayer wheel, a mechanical device that has a mantra or sutra passage encoded on it. Reciting the mantra orally is meritorious. Spinning a wheel with that mantra encoded on it carries the same merit but may be more efficient or accessible — for instance, an illiterate person who cannot read a sutra can still spin a wheel encoded with it.