Downstems

Diffuse the Heat: Downstems Made for Cooler Clouds

A downstem is the glass tube that connects your bowl to your bong’s water chamber, pulling smoke down into the water to cool and filter it. The right downstem helps maintain proper airflow and keeps your setup functioning as intended, whether you’re replacing a broken piece or upgrading your current one. Our collection includes 10mm, 14mm and 18mm glass downstems in standard, diffused, showerhead, slitted, and more perc styles, plus silicone downstems, in 3-inch to 6-inch lengths. 

Which Type of Downstem Is Right for You?

The right downstem depends on your bong’s joint compatibility, your preferred airflow, and desired level of water diffusion.

• Standard downstems: A simple, open tube for direct airflow and easy cleaning.
• Diffused downstems: Slits or holes at the tip create smaller bubbles for increased water diffusion.
• Perc downstems: Built-in diffusers, such as showerhead or multi-hole designs, provide additional water diffusion and can change draw resistance.
• Angled downstems: Designed with an angled connection to fit specific bong joint positions.
• Female downstems: Connect to compatible male joints, so check your bong’s joint type before choosing one.
• Silicone downstems: Flexible and less prone to breaking than glass, but you should confirm heat resistance and joint compatibility.

For more diffusion options, see our diffused downstem bongs. You can also pair your setup with a compatible ash catcher for an additional filtration stage.

How to Match the Right Downstem to Your Bong?

Match three specs: joint size, downstem length, and joint gender. The joint size must match your bong’s opening, typically 10mm, 14mm, or 18mm. The length determines whether the tip reaches the water without touching the base.

How to measure your downstem:

1. Check your bong’s product listing or look for a size marking near the joint.
2. If it’s unmarked, measure the inside diameter of the bong’s female joint in millimeters.
3. Measure your current downstem from the top of the frosted joint to the tip.
4. Confirm the tip will sit just below the waterline without touching the base.

For more detail, read our guide to glass joint sizes and shapes.

Quick Replacement Guide

• 10mm female joint: Choose a 10mm male downstem.
• 14mm female joint: Choose a 14mm male downstem.
• 18mm female joint: Choose an 18mm male downstem.
• 18mm bong with a 14mm bowl: Check for a compatible reducer downstem or adapter that fits both joint sizes.
• Unsure of the size: Measure the joint before buying. If the sizes differ, a bong adapter may help.