Metacaulk MC 150 is an elastomeric, one component, general purpose firestop sealant. Fire rated sealant and smoke seal for construction joints and through-penetrations on both horizontal and vertical surfaces. Water-based, non-sag caulking grade sealant that is easy to apply as well as to retrofit. Cures to a paintable flexible seal. Prevents the spread of flames, smoke, hot gases and water through joint openings and through-penetrations. Can be used in areas under constant vibration or movement. Excellent freeze/thaw. Recommended for metal, fiberglass and plastic pipes, wall construction joints, power and telephone cables. Tested to ASTM G21 mold inhibitor. Sound Transmission Class (STC) rating 65. (ASTM E90) VOC compliant. 3 year shelf life. Meets ASTM E814, Standard Test Method for fire tests of Penetration Firestop Systems.