Also known as the rolling prayer drums or prayer wheel, it is called Mani in Sanskrit. Traditionally, the mantra Om Ma Ni Pad Me Hum is inscribed in Sanskrit on the wheel. Chanting of each of the syllables helps purify each of the six realms of existence of the negativity associated with it. Om purifies bliss and pride (realm of the gods) Ma purifies jealousy and the need for entertainment (realm of the jealous gods) Ni purifies passion and desire (human realm), Pad purifies ignorance and prejudice (animal realm), Me purifies poverty and possessiveness (realm of the hungry ghosts) and Hum purifies aggression and hatred (hell realm). The prayer wheels come in many sizes.