FlameSafe® Electrical Box Inserts FlameSafe® For Electrical Data Sheets: (MSDS, PDS, etc…)Product Data SheetMetacaulk® 1000 is a water-based, flexible, highly intumescent 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. Metacaulk® 1000 will prevent the spread of flames, smoke, hot gases and water through joint openings and through-penetrations. No dilution or mixing is required for use. No special skills are necessary for installation. Metacaulk® 1000 has passed ASTM E 1966/UL 2079 for top of the wall applications with or with out backing and as little as 1/4 inch depth of caulk. The test assembly was also subjected to 500 cycles on a specially built machine that successfully demonstrated the product’s durability and movement characteristics.