Glass spinner coin/carb cap 3cm diameter and 5mm thick.  The cap is etched with 8 shallow arc shaped engravings to allow a small amount of ambient air to be draw into the banger in a circular motion, encouraging your pearls to spin and stir the concentrate.  On the flip side of the cap is a beautiful flower of life design.  Works best with a straight walled banger (like our etched leaf banger).  The combo comes complete with 2 glow in the dark 6mm terp pearls.