Metacaulk 1000 is a water-based, flexible, highly in tumescent sealant designed for use on metal, insulated, fiberglass and plastic pipes. It can also be used for top of the wall construction joints, as well as power and telephone cables. Sound Transmission Class (STC) rating 62, Tested in a UL 411 wall assembly/section to ASTM E90. Thousands of applications tested in accordance with ASTM E-814 for through penetration fire stops systems.