DuraFlex 250FR SBS is a fire-resistant, granule surfaced, premium SBS (Styrene-Butadiene-Styrene) mop or cold applied membrane. Manufactured with a heavy-duty, high performance non-woven polyester mat for higher tear strength and puncture resistance. It is saturated and coated with high quality, asphaltic bitumen and SBS elastomers for a durable, flexible and easily maintainable membrane. Designed for use as a cap sheet in modified bitumen SBS roof systems.