TOP SEALING Silicone Coated Fiberglass Rope 3300S-SILICONE is fabricated braided type E fiberglass and then coated with a high grade high-temperature silicone rubber.Silicone coated fiberglass rope is most often used as a seal where a high degree of air or gas or liquid tightness is required. The product is an ideal gasket where you require thermal performance plus resistance to wear and exposures.