The downstem is a critical component of any bong; it passes the smoke from the bowl to the water for filtration. Some bongs come with a downstem built in which make for good smoke delivery and a nice integrated product. The downside of this approach is a difficult to clean apparatus, with resin and ash retained in the nooks and crannies of the bong. For this article we will consider only removable downstems and explore the pros and cons of the various types.
Most common among removable downstems is the 18/14 mm taper. These have an 18 mm male taper on the outside for engagement with the bong, and a 14 mm female taper for acceptance of the bong bowl. The next consideration in downstem selection is length. When a downstem reaches all the way to the bottom of the bong it maximizes water filtration as bubbles rise through the water. If the downstem is too short only partial filtering will take place, if it’s too long the tapers won’t mate and the bong will not function.
If you need help sizing your bong or downstem, check out our sizing guide.
If your downstem is stuck in your bong, check out our removal guide.
Basic Glass Downstem
Also known as the underwhelming sidekick that reluctantly accompanies your bong purchase. Their primary function is shuffling smoke down into the bong water for a lackluster filtration experience. They generally have slits and a hole at the tip where large bubbles rip out into the water. A major shortcoming of this stem is their fragility, they commonly break when cleaning, and then you have to shell out another $15+ for a replacement. If you have multiple bongs with missing downstems you will have to buy the correct length for each waterpipe.
With better bubble dispersion, these stems are a step up from the basic glass downstem. For an explanation why smaller bubbles are better, check out our analysis here. Made from glass, these stems are easily broken and can cost $30-$40. Due to the small holes at the diffuser these stems can be a pain to clean, especially if you don’t use an ash catcher to limit crud in your rig. Using a bong bowl and ash-catcher in one, like the Invincibowl, will remove this cleaning nightmare.
Gorgeous and handcrafted, these stems add flair to your bong. They will typically have a better diffuser than basic glass downstems, and come in a wide range of color combinations and patterns. Being made of glass, they have all of the downsides of the previously mentioned products. With prices ranging from $50-$150 you’d better be sure you get the right size and be extra careful during cleaning time.
These unbreakable downstems are a great alternative to glass. They mimic the geometry of a basic glass downstem, but change the material to a colorful silicone. Some models even have segments which allow the assembly of longer or shorter downstem stacks. Silicone will discolor with continued exposure to smoke, rendering these stems limited in life cycle if you are concerned about presentation. For $15, the silicone downstem is an okay option.
Typically made of aluminum, these unbreakable downstems are more durable than silicone. Aluminum downstems come with discrete segments, making the length ‘adjustable,’ but the manual adjustments, though touted as a feature, feel more like a hassle. Repeated disassembly and cleaning can strip the segment threads, rendering the entire unit useless. Besides being manually adjustable, they function like basic glass downstems in airflow and fit with bongs and bowls. Coming in at $20-$30, they are a step up from glass.
Unlike any other downstem on this list, the Invincipole boasts telescoping-technology, which allows for length adjustment by sliding. Any size downstem can be achieved with this technology making sure the bubbles get right to the bottom of the bong, see why that’s important here. The Invincipole also houses an ash defense screen in the tip, right before the multi-hole diffuser. But there’s more, the pressure lock-and-release taper ensures that the downstem will stay engaged with the bong when you want it to, and a simple off-axis push will release the taper guaranteeing that the Invincipole will never get stuck in your bong (see the video here). Combine this with the anti-roll hex head and durable hard anodized coating and you’ve got the best downstem available. For the price of three broken glass downstems, the value of this novel downstem is worth the $50 investment. Step into the future – where every toke is a journey into excellence, and mediocrity is left far behind.