Specially designed water pipes, incorporating particulate filters and gas-dispersion frits, would likely be most effective in this regard; the gas-dispersion frit serves to break up the smoke into very fine bubbles, thereby increasing its water-contact area." These frits are commonly referred to as for the way that they diffuse (or disperse) the smoke as it exits the downstem, and usually consist of small holes or slats at the end of the downstem. This study suggests that a bong's smoke is less harmful than unfiltered smoke.