A device in a bong or dab rig that diffuses smoke when in water, creating a smoother, cooler hit. Usually attached to or replacing the downstem, diffusers create many smaller bubbles than a traditional downstem, increasing surface area and cooling the smoke. Diffusers can also quiet the sound of a bong or dab rig. 

“I only smoke out of a bong with a diffuser, otherwise it’s too harsh.”

Benefits of a diffuser

Diffusers, like percolators, aren’t necessary for a bong or dab rig to function, but they upgrade the smoking experience. 

By breaking up smoke before it hits water in the main chamber of a bong or dab rig, a diffuser creates more bubbles. This increases surface area, allowing the water to be a more effective cooling agent. Diffusers can make the smoking or dabbing experience more enjoyable by reducing coughing and throat burn.

Smaller bubbles can also make a bong or dab rig sound quieter. Large bubbles make a lot of noise, often described as a chugging sound, but small bubbles produced by a diffuser sound more like a gentle roll that can go unnoticed—great for discretion. 

How to use a diffuser

A bong or dab rig may come with a diffuser, but if not, diffusers can usually replace removable downstems, but not fixed downstems. Make sure you find a diffuser with the same fitting size as the downstem, and you can usually swap it out. Then, use the bong or dab rig as you normally would. A diffuser doesn’t change the way a bong or dab rig is used, it simply enhances the experience.