This material is a fiberglass fabric which is composed of chopped strands woven into a flat matting. This matting can be torn easily and is the most common type of fiberglass used. This material was made by reputable manufacturers across the US, and their long lasting presence in the composite industry will ensure you receive a quality material.
The binder on the material is intended for use with polyester and vinylester resins. Epoxy will have a difficult time wetting out the material.
This is a sample sized at 4″x4″.