... instruction: OD,hole size,Qty of holes, content of alumina(if you are not sure,pls inform usage high temperature ... Ceramic insulated alumina tube Application:Our ceramic tube are mainly used as ... Mechanical and electrical field,and so on Material:75% alumina, 90% alumina,95%alumina,99%alumina,99.7%alumina or Zirconia , corundum Available sizes:Dia of the ...