3M™ Fire Barrier Moldable Putty Stix MP+ Is A One-Part, Re-Enterable, Intumescent Putty That Can Be Easily Formed to Firestop Through Penetrations and Blank Openings In Fire-Rated Assemblies. We Formulated This Dark Red, Easily Moldable Putty Stick to Provide Up to 4 Hours Of Fire Protection. These Putty Stix Also Produce A Draft and Cold Smoke Seal and Help Reduce Noise Transfer.