A screw driven adjustable endstop for maximum accuracy for your Prusa Mendel i3 (Vanilla Version). For the adjustable z-endstop you will be needing Just print the part, screw it on the x-motor mount (using the same screw used for the x-motor), insert one nyloc nut inside the rectangular slot (heat gun may be needed), insert the screw and add the other nyloc nut at the end of the screw (to increase the area pushing the endstop). Just screw and unscrew to get optimum z-home distance!