Linear rail adapter bracket for the X axis. This is to replace the aluminum extrusion all together giving you back that missing range if you decided to use linear rails. This will fit MGN12 rails at 300 mm length of rail without sacrifice of any range. It does require M3 screws and nuts, I also use a 10-24 screw and nut as well to attach to the brackets that travel along the Z rail. I did need a bit more belt length.