Heat-resistant sealing cords are made of textured glass fiber yarn, which is braided and used for sealing and joining in places where resistance to high temperatures is required. Hard cords are made of three pre-twisted strands that are braided together as a cord. Usually it is used to connect the chimney system with furnaces and to seal the external and internal doors of the furnace and its body. Nominal temperature up to 550 C. It is recommended to mount it with a cord glue.