Waste board exact dimensions for 1000, building your own

what are the exact dimensions for the 1000mm waste board

There is a cad file for it.
https://workbench.grabcad.com/workbench/projects/gcl5zpCuwqCXWLvYktLQBc-2IHvossNo37ycTOkzg6gREW#/space/gcojYwyy_VqboQQ-9hKBJrjS3zGaGuue8sfnqRNxGI9WQS/folder/2078599