Percolators force the smoke created while using your bong to further diffuse through the water. When the smoke is forced to diffuse more, that means more of the smoke is coming into contact with the water before you inhale it. This results in extra smooth, extra cool, and extra tasty hits that many bong users swear by. Percolators can greatly increase the price of a bong, so be sure to take time to consider all of your needs before you commit to purchasing an expensive bong.