This Green Grace Glass Precooler is a unique smoking accessory for your bong! It is used as an additional precooler for your smoke before the latter enters your bong and ends up in your mouth. So it furthermore smooths your smoke, improving your smoking experience on the whole! It is made of a high quality heat proof borosilicate glass, formed in the shape of a scientific tube. It includes a slitted chillum percolator that bubbles up your smoke. The percolator ends up to a sure ground of 18.8mm diameter, connecting to a 3 point slide bowl on top of it for placing your herb or tobacco.