This is a standard Chinese cheese. I checked them under a 40x microscope. They look like they were made on a manual cutting machine and then just tossed in the bin. All cutting edges are slightly serrated, and there were even burrs on the corners of the cutting teeth, as can be seen in the photo. For comparison, I've added a photo of a new American-made vinyl cutter. At the same time, they are sharper than other Chinese knives I've bought before. But.