The OG Original 16.5-inch is a beaker-in-beaker design, with a second beaker chamber set inside the base for extra water volume and filtration, so the smoke gets cooled and diffused more than in a single-chamber piece. It's built in thick 7mm borosilicate glass for durability, with an 18mm bowl joint that takes a standard 18mm bowl. At 16.5 inches it's a tall, substantial daily piece with a stable base. A strong choice for someone who wants heavier glass and the extra filtration of a beaker-in-beaker setup.