Swiss Perc
Swiss percs are more decorative than anything else, but they do still have some functionality to offer in terms of filtration and cooling. These percs are named due to their resemblance to Swiss cheese, formed in a vertical disc shape with lots of holes. more..
The smoke and vapor inside your bong is forced to travel around the holes of the Swiss perc. This process helps to cool the smoke and purify it slightly by removing certain toxins and carcinogens. This results in a smoother and cooler hit at the end, but the level of filtration provided by a Swiss perc isn’t quite as strong as it would be on something like a matrix or honeycomb perc.