Fire Barrier Composite Sheet, Length 28 In., Width 16 In., Silver, 2 hr. Fire Rating, Material Intumescent, Standards UL Classified Fire Barrier ProductsComposite SheetsFire-stop large openings through fire-rated walls and floors with multiple penetrations. Anchor sheets to the wall or floor with common tools. Cut to fit irregular shapes.STI brand sheets expand up to 15 times their original size, are UL Classified, FM approved, and meet ASTM E814 (ANSI/UL 1479) standards. 3M brand products can fire-stop openings up to 36 sq. ft. and are UL Classified and FM approved.