If the Bottle portion of your Medium Gravitron is damaged or misplaced, this new bottle will get your Gravitron going again. The bottom of the bottle slides into the vase and creates the seal. The bowl fits in the mouthpiece and fills the vase with smoke as you pull up on the bottle while lighting the bowl.   Type of Smoker: Heavy/Collector These are for a person who’s purchased a Gravitron in the past. They need parts.