This scientific glass bong features an inline perc chamber, as well as a donut percolator. Combined, these two percs create perfect diffusion for silky smooth, flavorful hits. The donut perc not only looks cool, but it's also highly functional. This design filters your smoke and also blocks water from splashing up into the your mouth (a rather unpleasant experience). Thanks to the strong glass construction and reinforced joints, this bong is definitely built to last.