Intumescent fire & smoke seals are designed to seal the gap between door & frame in the event of a fire. They consist of a graphite based material encased within a robust PVC carrier of overall thickness 4mm. Heat from a fire causes the intumescent material to expand & seals the door & frame. The smoke brush substantially reduces the transfer of smoke & toxic fumes between the door & frame before the fire expands the intumescent compound. Supplied with self adhesive backing tape.