Introducing Quartz Flakes- a line of quartz accessories shaped like propellers or snow flakes. Designed to spin like a fan (with the correct spinner cap), they add heat retention and mixing to your concentrate experience. This 18mm model is designed for Bangers and will work well with most models in the market place with an Internal Diameter of 20mm. This model has a thickness of 3mm & is slumped in the center for a pivot point.