A circular percolator is a type of perc made up of one or more rings with gaps between them. The rings have slits in the sides to allow smoke to pass through and diffuse. Circ percs are similar to showerhead percs which have holes or slits on the bottom. All percs help cool and smooth hits. Circ percs can be combined with other percs to increase diffusion. They provide an efficient way to diffuse smoke without requiring as much draw as other percs. “I decided to upgrade my bong and get one with a circ perc instead of the tree perc I had before. The hits are much smoother now.” Circ percs are ideal if you want to add percolation without increasing draw resistance too much. The circular shape and side slits provide ample diffusion while still allowing smoke to pass through easily. Stacking circ percs or combining with other styles creates even more bubbles and cooling. Circ percs strike a good balance between diffusion and draw resistance.