S-Glass Cloth is manufactured similarly to E-Glass Cloth, but with a different sizing (coating). Thus, S-Glass Cloth is stronger and tougher that E-Glass Cloth and has 20% greater tensile strength. S-Glass Cloth provides a premium multi-stage finish and has the highest impact strength of all fiberglass materials. This material is categorized by weight per sq. yd. and is sold by the running yard or in bulk by the 125 yard roll.