DynaLastic® 250 is a polyester reinforced SBS modified bitumen sheet that incorporates the features of a tough polyester mat that is saturated and coated with a blend of SBS rubber and high quality asphalt. The polyester mat provides excellent tensile strength, toughness, 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.