These incense cones work with the backflow burner you use special you place these at the top of the backflow burner.

The difference between backflow incense cones and normal incense cones is that there is a tunnel in the middle of cones. The air stays cool in this opening. Because air (and therefore smoke) flows down, the smoke will go down through the waterfall. To create a special effect, more smoke is released from a backflow cone.