(ISO 9001 approved factory!) 60-99.7 alumina ceramic insulation tube (different size and length available) Professional manufacturer of ceramic tube here for about 10 years, has exported to About 30 countries, good reputation has gotten, welcome to contact me for further info. 1.Thermocouple protection alumina ceramic tube are made of al203 , and alumina Content from 60-99.7%, length can do according to your demand. Od from 6-32mm, id from 4-30mm. 2.Alumina ceramic furnace tube, both end open, white, creamy, pink color.Od 8-110mm, Length can do as your requirement. 3.Alumina ceramic insulation tube , .2 or 4 holes, size do as your request. Hot selling kinds Are in stock. Polyfoam filled , wooden case outside