SpecSeal® Series SSP Putty is a non-hardening, intumescent compound. It is designed to seal through penetrations against the spread of fire, smoke and toxic gasses.  SpecSeal® Putty expands up to eight times its original size when exposed to high temperatures or flames. Also reduces sound transmission.  No tools required to install, can be hand packed into openings. Adhesive is aggressive enough to adhere to most building materials.  Putty remains soft and easy to reuse or retrofit. Faced on both sides with a convenient poly liner, SpecSeal® Putty Pads are easily applied with no mess or excessive residue. sized to fit a typical 1-1/2" (38 mm) deep 4S box with no cutting or piecing required. UL classified and FM approved. Color: Red.