SOPRALENE 250 Sanded is composed of a proprietary formulation of elastomeric styrene-butadiene-styrene polymer modified bitumen and is reinforced with tough, dimensionally stable non-woven polyester mat. The topside & underside are surfaced with fine mineral aggregate to facilitate cold adhesive and hot asphalt applications. SOPRALENE 250 Sanded is a SBS-modified bitumen base ply for use in approved multi-ply membrane & flashing assemblies.