Jar caps make a huge difference in how well container candles burn. Candles that are in jars run into a problem as the level of wax gets down farther and farther into the container. The issue is caused by hot air trying to get out and cool air trying to get in. This fight between hot and cool air causes turbulence which makes the candle flame bounce around and produce soot. This jar cap helps to regulate the air flow allowing the hot air to come out though the large center hole and cool air to be sucked it through the smaller outer holes. This results in a flame that sits still which will not produce soot like a dancing flame does. Watch our video to see just how well these jar caps actually work.