1.stainless steel , 2.tiwn wall 3.twist lock system and spigot system 4.thickness 0.5mm 5.insulation ceramic fiber A chimney system mainly includs straight pipe ,bend ,tee ,lock band , raincap . A good chimney can keep a clean environment, and keep warm.2.tiwn wall 3.twist lock system and spigot system4.thickness 0.5mm5.insulation ceramic fiber