Hi Si always makes scientific glass look easy, and they don't hold back on their downstems. These downstems are diffused with multiple holes surrounding a cylindrical shape. They are for use with a 18.8mm female joint and they have a 14.5mm female joint. These work as a replacement for existing Hi Si tubes and they will work great with any suitably sized pipe.


  • Clear Glass
  • Diffused Downstem
  • Highest Quality Materials
  • Thick Glass