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. LEVEL IV CERAMIC RIFLE PLATE – FuryArmorSystems