The mimeograph machine (commonly abbreviate to mimeo) or stencil duplicator, along with spirit duplicators and hectographs were for many decades used to print short-run office work, classroom materials and church bulletins. These technologies began to be supplanted by photocopying in the 1960s, although in mid-range quantities, mimeographs are still more economical than photocopiers. Photocopying and cheap offset printing have replaced mimeography almost entirely in developed countries. But mimeography continues to be a working technology in developing countries, since the machines are more energy efficient and no electricity is required.