The Air Pencil Tire Gauge Glass Tube is a fat glass stem with extra-thick walls and a big hole, which the listing says has a variety of uses. You can pair it with grommets as a parallel connector in a DIY bong, or simply use it as a stem. The specifications list the type as a stem tube and the material as glass, and the page notes that it is sold per unit. The tube measures 4.8 in [12 cm] in length.
The wide bore allows generous airflow, and the thick walls make the tube sturdy for its size, so it holds up better to everyday handling than a thin-walled stem. The clear glass is easy to clean and inspect, and at 4.8 in [12 cm], it is a handy length for custom builds, repairs and replacements. Because it is a simple, inexpensive part, it is easy to keep a spare on hand.
This tube suits hobbyists who like to build their own pieces, anyone who needs a replacement stem or connector and people who want a tough glass part for a project.
If you are looking for a fat, thick-walled glass tube for DIY builds, stems or connectors, take a look at the Air Pencil Tire Gauge Glass Tube.