Bio Soluble (Calcium Magnesium Silicate) Fibre Sleeving: our fibre sleeving has special bio soluble (body soluble) yarns developed as a direct replacement for harmful asbestos and ceramic fibre products. The bio soluble fibre insulation is rated to 1000°C in situ. Its wire reinforcement is rated to 1000°C with the glass reinforcement rated to 550°C.