The 10-inch Dabitron Bubbler Downstem is an interchangeable part designed specifically to fit the Gravitron bong. To put it simply, it allows you to turn your Gravitron bong into a fully functional dab rig. And when you consider the Gravitron’s size, that means you transform into a concentrate-ripping behemoth. This diffuser downstem is made of thick, durable glass and comes with a 14.5mm female domeless quartz nail. Expect some seriously impressive heat retention! The downstem also sports a male 14.5mm joint that fits your Gravitron. It’s decorated with the legendary Grav Labs logo and is the most affordable way to turn a legendary bong into a legendary oil rig.