The 3M™ Fire Barrier Pillow is a self-contained highly intumescent product designed to firestop a wide variety of through-penetrations including cable trays (up to two per opening), conduit and blank openings, which penetrate fire-rated construction. Available in three sizes to fit all applications. Up to 3 hours of Fire Protection. During a fire, 3M Fire Barrier Pillows intumesce (expand) and lock themselves into place, completely surrounding the penetrant(s) stopping smoke, fire and toxic gases fro