1. I am not sure that this is actually silk 2. I have other silk pillow cases and they do not get pulled threads (runs) in them after even a few years. Within one week of use my "silk" pillow case has two pulled threads. I am happy that I did not get more. I would have if the quality was average. They feel more like satin polyester.

This is not real silk, just satin. It's great if you don't mind the difference, but not what I was hoping for. I've gotten the others they sell with a zipper and those are real silk, but the zipper breaks easily. This is a nice size and has pocket flaps in the back so your pillow won't slide out, so 2 stars for that. Just wish the description was accurate.