The covered in the section protruding both holding "tongues" on the long sides of the sheet are A stepped, ie in ideal cut has been executed holds the sheet of itself, because it gets stuck in the wood (etc.). This fixture has come back cut on the respective sides that they do not interfere with the lateral supports of the sheet (on the short sides), in this case was thought along.
I have to cut to the measure specifications with jigsaw cut (in a 19 mm pressboard plate) - the sheet fitted easily at first.
One can recommend without restriction!