Designed to Expand Up to 5 Times In Volume After Dispensing, 3M™ Fire Barrier Rated Foam Fip 1-Step Is A Two-Part Urethane, Smoke, Sound and Firestopping Foam. This Intumescent Foam Can Be Used to Fill The Annular Space Created By Pipes and Cables Penetrating Through Fire-Rated Construction. It’S An Alternative to Mineral Wool, Bricks, Pillows and Runny, Ineffective Foams and Is Ul Listed.