The ceramic Centre rod is constructed from a porous white glazed ceramic. A plastic ring constructed from polypropene sits beneath the tank. There may be an o-ring created from a silica gel compound that helps seal the ceramic rod in the plastic ring at The bottom with the cartridge. https://buydelta8vapecarts41840.imblogs.net/76733480/the-definitive-guide-to-marijuana-edibles-for-sale-online