Phoenix Star designs a unique freezable bong, Phoenix Star Beaker Bong 5mm Thick Freezable Coil 12 Inches PHX496. Both the downstem and the bowl are filled with medical grade glycerin. The high grade glycerin will not expand when frozen. And this glass bong is also equipped with a longer glycerin coil. You can place the freezable glycerin bong in your refrigerator for 1-2 hours or more before you start smoking. Then you can gain cooler and smoother hits. Made from premium boros glass, this glycerin coil bong comes with a height of 12 inches and a thickness of 5mm for durability. The glycerin bowl of the freezable glass bong is removable, easy to replace.