3M™ Fire Barrier Self Locking Pillows combine intumescent fire-rated material and a range of sizes with interlocking strips that allow installers to easily lock multiple pillows together without tools. Installers can also cut and reseal the pillows in the field. This makes it easier to assemble ideally-sized firestops for specific penetrations in floors and walls, installed to the correct compressions for maximum effectiveness in new construction or retrofit applications. No wire mesh, steel cover plates or other additional support is required. The pillows are fully re-enterable and reusable - the interlocking strips can be released by hand, making it easy to reconfigure firestop pillows as additional services are added or relocated.