Rmax TSX-8500 is an energy-efficient thermal insulation board composed of a closed-cell polyisocyanurate (polyiso) foam core bonded to embossed, glass fiber reinforced aluminum foil facers on both sides. The exposed side of the board has a heavy embossed 12mil facer with an aluminum reflective surface and clear coating for limited protection against oxidation. The other side is marked in production to ensure proper installation.