Made of EPDM, Master Flash is compounded specifically for maximum resistance to weathering due to ozone and ultraviolet light. Provides a permanent seal that controls gaseous or liquid environments to eliminate leakage and odor contamination. Base is made of heavy-duty aluminum alloy for flexibility and corrosion resistance. Excellent for corrugated steel roofs. The stepped-cone design makes Master Flash easily adaptable to every roof pitch. Master Flash performance is unaffected by ice and snow, hail stones, vibration, expansion and contraction.