excerpt from Tibetan Furniture, Chapter 2: "Forms and Uses": prayer wheels
"Prayer wheels are such a universal feature of Tibetan life that they have become a symbol of the country. Tibetans believe that the spinning of the wheel is equivalent to the recitation of the prayers that are written on a strip of paper, wound tightly and packed inside each wheel. Prayer wheels come in many different forms, from the hand held wheels (fig. 36) of pilgrims to huge wheels which have their own chapels to house them and which can be pushed simultaneously by several worshippers."
"The functions of the two uniquely Tibetan items of the reading desk (pegam) and the prayer wheel reflect different paths for gaining merit in the Buddhist religion: for the studious there is the path of meditation on religious texts, a severe and demanding course, while for the ordinary worshipper there is the path of simple faith, demonstrated through pilgrimmage and the recitation of prayers and mantras. Prayer wheels facilitate the second path and ensure it is open to all, even those who lack the education to follow the details of the teachings".
Tibetan Furniture by Chris Buckley