RepRapPro extruder drive for RepRapPro's Tricolor Mendel, Mono Mendel and Huxley.
For printing instructions, see: http://reprap.org/wiki/RepRapPro_mini_extruder_drive_printing
Assembly instructions are much the same for all the printers that use them (Huxley, Mono/Tricolour Mendel, Huxley Duo, Mendel 3). Refer to the build instructions for your printer: https://reprappro.com/documentation/