29mm Joint Diffuser Base.  This Build-a-Bong® straight-style base includes a 29mm joint to support our larger diffuser downstems.  These 6 arm diffuser downstems come in a range of colors and are great at filtering smoke and ash.  The removable downstem makes this base easy to clean and allows it to be customised even further.  Looks great with any Hoss Glass® middle or top pieces!