- For applications requiring conformable coverage, these pliable 3M™ fire barrier moldable putty pads mpp+ meet a full range of firestop needs that would be impractical with strips, wraps or rolls. Ready to use in convenient 1/10 in (2.54 mm) thick pads, this firestop material is designed for excellent adhesion to most construction substrates and is non-corrosive when applied to metal - ideal for use with listed steel or plastic electrical outlet boxes. It is also safe for applications including synthetic cable jackets, making it suitable for firestopping cable bundles. It won't crumble or dry out, exhibits excellent aging properties and is re-enterable to save time and money after installation. And the pads are extremely simple and cost effective to install: technicians mold the material by hand directly onto the substrate without mixing or tools. For larger applications, self-adhering pads can be molded together.