The UIC | Two Neck Bottom Flask NSH 29/32 (4 L) is a 4 L borosilicate glass two-neck round-bottom flask for use as a feed or collection vessel on UIC KDL5 molecular distillation systems. The dual NSH 29/32 ground glass neck configuration provides connections for feed introduction, heating, or vacuum access, depending on the position in the distillation train. An OEM UIC replacement glass component; inspect regularly for chips or cracks that could compromise vacuum integrity.