CORCIO Backflow Waterfall Cones Specifications: 70 cones (high 1.1 Inch diameter 0.5 Inch)about 21 minutes a cone Principle:because the density of smoke is heavier than the air density, smoke flow from the high down like a waterfall Place:study, livinoom, meditation room, yoga room and so on Warm Tips: Use it with backflow incense burner and without wind Althought it has no fire, pls put it in a safe place.Be careful