These are sheets of thin (.007 inch) Fiberglass circuit board material (used in making multilayer boards, called prepreg) that measure 18 x 16 inches ( I roll up & ship) that makes an EXCELLENT cover for antennas, horn mouths, as a flat radome, etc, really cool for projects.  Some have a white mark on them, does not affect utility.  Easy to cut with scissors.  Price per 2 sheets, I have added one to the sale as shipping prices keep going up and you get a better deal. Please see my other stuff for more useful bits & pieces.