Johns Manville JMCleanBond® SBS Cap Flashing is a self-adhering, modified bitumen sheet incorporating the features of a 170 g/m2 polyester mat with a blend of SBS rubber and high-quality asphalt. 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 weather and foot traffic. The polyester mat provides good tensile strength, toughness, puncture resistance and can accommodate stresses created by typical rooftop expansion and contraction forces.