Ironing Sheet? What is it and what is it made of?

I'm not sure. Silky smooth a type of material that you iron on so that the back of stitches don't scratch. On the package it said use a Iron Sheet.

are you wanting to know about a pressing cloth, or an ironing blanket? A pressing cloth is something that is placed over your item to iron so that it does not mark the material. Am ironing blanket is a heat resistant product to iron on so as not to damage the surface you have placed it on. My mother used a linen type fabric for the pressing cloth. I have a soft product that I purchased for it, and not sure what it is made of.