This is a quick and simple mod for those of us with the 10" Makerfarm Prusa i3v. This part mounts to the underside of the X-axis rail. The original placement of the z-end stop has been moved from the front to the side of the z-axis rail. Use a 30-40mm screw with a nut on it to thread into the part, and adjust to make contact with the end stop. I find this is an easier alternative to adjusting the z-height than moving the entire end-stop.