Across International 537C 1/2" Fiberglass Rope for Insulating Boiling Flask, 20'1 2" high temperature, ultra conformable fiberglass rope, theyre flexible and will conform to uneven surfaces. The looser construction also makes them more likely to absorb liquids. Push them into the groove thats commonly built into oven doors, furnaces, and tanks. These high quality fiberglass rope resist bleach, solvents, and most acids (do not use with hydrofluoric acid, hot phosphoric acid, and wet hydrogen chloride). CAUTION! Always use proper