The GRAV Gravitron 2.0 Bong has a new and improved design, constructed with glass five times thicker than previous Gravitron pipes. The upgraded grommet is made from platinum cured silicone and ensures a tight seal with the outer chamber to prevent any smoke escaping. The flanged neck at the top makes it easy to lift the bottle. Defy gravity with these top quality gravity bongs! Each gravity bong includes a funnel style male herb slide. Available in 2 sizes to suit your next sesh!