This bed level test will tell you if your bed is leveled correctly. It should be 0.25mm in height everywhere. If itis not, you know if it's under extruding or over extruding. Its size is 200mm x 200mm so if there is another printer that will fit this then you can use this on it too. The build volume of the i3 Mega is 210mm x 210mm x 200mm. This is purposely undersized.