These bong diffusers are water pipe additions which slide inside the bong to create more bubbles. You can find diffusers in all kinds of shapes, colors and different prices but the most important thing when it comes to diffusers is the number of slits they have. The more diffuser slits you have the more bubbles will be created. The more bubbles are created the better the smoke will be mixed with the water thus more cooler and smoother hits you will get.
A bong diffuser simply slides into the bong's water chamber and the glass bowl goes on top of the diffuser. Also you can add a downstem diffuser to your ash catcher (only the dobule ash catcher's permit that and not all) for extra bubbling. These images show how a downstem diffuser can be added to your bong.
In the first picture from the left, the six arm downstem diffuser is being connected to the ash catcher's chamber and a glass bowl is added on top. The diffuser's 18 diffuser slits and the ash catcher's 4 diffuser slits are working together to provide a crisp and smooth smoke experience. Additionally, a user can connect an extra six arm downstem that will connect the water pipe and the ash catcher so you will have 40 diffuser slits. Now that's what we call a clean smooth hit. To see more about the double ash catcher follow the link.
The second picture shows how to connect a six arm downstem diffuser to the water pipe and then to a swirl ash catcher. simply slide the downstem into the bong's water pool and the connect the ash catcher's 18.5 mm glass on glass connection piece to the six arm downstem and you are ready to go.
In the fourth picture we are using only the 6 arm downstem and the glass bowl. The downstem diffuser will slide into the bong's water pool. As you can see in the fifth picture, the downstem diffuser features 6 legs, each leg having 6 diffusers slits for a total number of 18 diffuser slits. To see more about the six arm downstem diffuser follow the link.