joints:19# 24# material:borosilicate 3.3 all sizes:16*200/ ... /24 30*200/24 etc (1)item:Chromatography column,with joints,fritted disc,PTFE stopcock(2)material:heat resistant 3.3 ... interested in our products, please contact us. Chromatography column,with joints,fritted disc,PTFE stopcock