3M Fire Barrier Red Intumescent putty pad Caulk Model #MP+6 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. Firestop tested up to 4 hours in accordance with ASTM E 814 (UL 1479) and CAN/ULC S115 Putty provides draft and cold smoke seal Pliable and conformable design easily molds into required shapes Helps reduce noise transfer (STC-Rating of 56 when tested in STC 56-rated wall assembly) Will not dry out or crumble for a re-enterable and repairable solution Excellent adhesion and aging properties provide a long-term performance Noncorrosive to metal and compatible with synthetic cable jackets Low VOC, halogen-free and solvent-free formula for safe working environment with minimal odor