Ashcatchers add a second degree of filtration and cooling to your glass piece. These are known to really level up the way a bong or rig will feel. You will have cooler, and better filtered smoke when using an ashcatcher. On top of that, they will also help keep your expensive glass setup clean. Ashcatchers come in many different shapes and sizes. Make sure you are buying one with the proper size connection. Percolated ashcatchers will add a second layer of filtration to a percolated glass piece. Many people say once you start smoking with an ashcatcher attached to your bong, it's difficult to go back.