Insulation sleeve is a kind of mica insulation sheets, is a collectively. The insulation sleeve is made of high quality muscovite paper or phlogopite paper with high-performance organic silica gel bonded by the processing of the rigid tubular insulation material. Insulation casing (mica casing) has good electrical insulation performance and high mechanical strength, insulation casing (mica casing) cooperation in a variety of electrical appliances, electrical, electric smelting furnace and other equipment in the electrode rod or outlet mica casing insulation. Compared with the traditional ceramic tube, insulation casing (mica casing) with wall thickness and oval degree easy to control, discharge evenly, not broken, etc., polyimide glass fiber(mica casing) is the ideal alternative to some ceramic tube. Insulation sleeve (mica casing) is divided into hp5 mica tube temperature 500 ℃, hp8 gold mica tube temperature 800 ℃.