A downstem diffuser has small slits or holes at its base that break smoke into tiny bubbles as it passes through water. This process increases surface area and improves filtration. The result is smoother, cooler hits compared to a standard downstem. Diffused downstems are also a common upgrade in many bongs for better performance.
The 14mm GRAV® Fission Downstem fits 14mm beaker or straight tubes with angled joints. Its precision-cut fission holes provide smooth diffusion and resist clogging. Measures 3.3″, fits a 19mm joint, and holds a 14mm bowl or banger.