Amazing craftsmanship with a great functionality and durability. There are these dual spiral holes that create a vortex inside the banger.This vortex is responsible to spin the air and terp the pearls in order to agitate the concentrated material. This is done for a better vaporization. This quartz dual spinner cap provides two functions, one side acts as a bubble carb cap, while the flip side is a directional/spinner cap. Features: Material - Quartz Universally Compatible - Yes Outer Diameter - 30mm Spout Diameter - 8mm Spout Diameter when flipped - 18mm Auto Spin - Yes Recommended Pairing