SOPRALAST 50 TV ALU is composed of a proprietary formulation of elastomeric styrene-butadiene-styrene polymer modified bitumen and is reinforced with a high strength glass scrim. SOPRALAST 50 TV ALU is a SBS-modified bitumen cap ply for use in approved multi-ply membrane and flashing assemblies. The topside is surfaced with an aluminum foil and underside is surfaced with polyolefin burn-off film to optimize heat welding.