Phoenix Star Freezable Coil Glycerin Bong With Matrix Perc 7 Inches PHX18 is made of high-quality borosilicate glass, you can see the bubblers stack via the clear glass. It is 7 inch tall and comes with a 8 inch freezable coil part which can be put in freeze before you start. The diffused downstem is fixed inside the bubbler to keep it from damage. This well design bubbler pipe features a matrix percolator for better filtration, smokers will enjoy super smooth smoking experience. The freezable coil can be easily removed, also ideal for travel. Blue, black and green colors are available for you and your customers to choose.