DynaLastic® 250 FR is a fire-resistant polyester reinforced SBS modified bitumen sheet. This product incorporates the features of a tough polyester mat that is saturated and coated with a blend of SBS rubber, high quality asphalt and fire-retardant additives. The polyester mat provides excellent tensile toughness, strength, puncture resistance and can accommodate stresses created by typical rooftop expansion and contraction forces. The elastomeric asphalt blend has full recovery properties after 100% elongation and lends elasticity and flexibility to the sheet. The covering layer of ceramic-coated roofing granules provides durability along with superior resistance to damage from foot traffic.