What is the Teltron tube?

From a channel Lumen includes in full: Random Experiments International demonstrates chemistry experiments and syntheses (titrations, aldol condensations, singlet oxygen) with explanations of the reactions and theory.

A 3-minute video from Random Experiments Int. - Experiments and syntheses's catalogue; the title names its topic.

Video by Random Experiments Int. - Experiments and syntheses, played through YouTube's embedded player.