DuPont™ Tuff-R™ Polyisocyanurate Insulation consists of highperformance, high R-value, closed-cell polyisocyanurate foam core boards sandwiched between a choice of durable exterior foil facers. The polyisocyanurate insulation is created by an exclusive free-rise manufacturing process, which produces a uniform, closed-cell foam for better foam quality than conventional restrained rise process. On Tuff-R™ Insulation, one facer is a continuous sheet of aluminum foil; the other is a durable tri-laminate facer consisting of aluminum foil, kraft and metalized polyester film and Tuff-R™ helps reduce air infiltration through the wall by covering cracks between the framing members and sealing tightly against the studs.