Dow Corning 3-6548 silicone RTV foam kit is a medium-density, two-part product supplied as A and B liquid components. The A component is black and the B component is off-white for easy identification and inspection of mix. When the A and B components are thoroughly mixed in a 1:1 ratio by either weight or volume, the product will expand and cure to a foamed elastomer at room temperature. A mild exotherm is exhibited during the curing reaction. - Dow Corning 3-6548 silicone RTV foam kit is formulated to have fire resistance properties and can be used for preparing fire-resistant penetration seals as evidenced by the results of fire endurance testing as defined in ASTM E 814 "Standard Method of Fire Test for Through-Penetration Firestops".